1. The /usr/lib/udev/rules.d/60-net.rules file defines that the /lib/udev/rename_device helper utility searches for the HWADDR parameter in /etc/sysconfig/network-scripts/ifcfg-* files. If the value set in the variable matches the MAC address of an interface, the helper utility renames the interface to the name set in the DEVICE parameter of the file.
2. The /usr/lib/udev/rules.d/71-biosdevname.rules file defines that the biosdevname utility renames the interface according to its naming policy, provided that it was not renamed in the previous step.
3. The /usr/lib/udev/rules.d/75-net-description.rules file defines that udev examines the network interface device and sets the properties in udev-internal variables, that will be processed in the next step. Note that some of these properties might be undefined.

4. The /usr/lib/udev/rules.d/80-net-setup-link.rules file calls the net_setup_link udev built-in which then applies the policy. The following is the default policy that is stored in the /usr/lib/systemd/network/99-default.link file:

   [Link]
   NamePolicy=kernel database onboard slot path
   MACAddressPolicy=persistent

   With this policy, if the kernel uses a persistent name, udev does not rename the interface. If the kernel does not use a persistent name, udev renames the interface to the name provided by the hardware database of udev. If this database is not available, Red Hat Enterprise Linux falls back to the mechanisms described above.

   Alternatively, set the NamePolicy parameter in this file to mac for media access control (MAC) address-based interface names.

5. The /usr/lib/udev/rules.d/80-net-setup-link.rules file defines that udev renames the interface based on the udev-internal parameters in the following order:

   1. ID_NET_NAME_ONBOARD
   2. ID_NET_NAME_SLOT
   3. ID_NET_NAME_PATH

   If one parameter is not set, udev uses the next one. If none of the parameters are set, the interface is not renamed.

Procedure

1. Boot the Red Hat Enterprise Linux 8 installation media.
2. In the boot manager, select Install Red Hat Enterprise Linux 8, and press the Tab key to edit the entry.

3. Append the net.ifnames=0 parameter to the kernel command line:

   vmlinuz... net.ifnames=0

4. Press Enter to start the installation.

Procedure

1. Edit the /etc/default/grub file and append the net.ifnames=0 parameter to the GRUB_CMDLINE_LINUX variable:

   GRUB_CMDLINE_LINUX="... *net.ifnames=0

2. Rebuild the grub.cfg file:

   • On a system with UEFI boot mode:

     # grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

   • On a system with legacy boot mode:

     # grub2-mkconfig -o /boot/grub2/grub.cfg

3. If you use interface names in configuration files or scripts, you must manually update them.

4. Reboot the host:

   # reboot

Procedure

1. Install the netconsole-service package:

   # yum install netconsole-service

2. Edit the /etc/sysconfig/netconsole file and set the SYSLOGADDR parameter to the IP address of the remote host:

   # SYSLOGADDR=192.0.2.1

3. Enable and start the netconsole service:

   # systemctl enable --now netconsole

Procedure

1. To open the service file in the editor, enter:

   # systemctl edit service_name

2. Enter the following, and save the changes:

   [Unit]
   After=network-online.target

3. Reload the systemd service.

   # systemctl daemon-reload

Procedure

1. To load a new configuration file:

   # nmcli connection load /etc/sysconfig/network-scripts/ifcfg-connection_name

2. If you updated a connection file that has already been loaded into NetworkManager, enter:

   # nmcli connection up connection_name

Procedure

1. Optional: Display the list of devices to identify the device you want to set as unmanaged:

   # nmcli device status
   DEVICE  TYPE      STATE         CONNECTION
   enp1s0  ethernet  disconnected  --
   ...

2. Create the /etc/NetworkManager/conf.d/99-unmanaged-devices.conf file with the following content:

   [keyfile]
   unmanaged-devices=interface-name:enp1s0

   To set multiple devices as unmanaged, separate the entries in the unmanaged-devices parameter with semicolon:

   [keyfile]
   unmanaged-devices=interface-name:interface_1;interface-name:interface_2;...

3. Reload the NetworkManager service:

   # systemctl reload NetworkManager

Procedure

1. Optional: Display the list of devices to identify the device you want to set as unmanaged:

   # nmcli device status
   DEVICE  TYPE      STATE         CONNECTION
   enp1s0  ethernet  disconnected  --
   ...

2. Set the enp1s0 device to the unmanaged state:

   # nmcli device set enp1s0 managed no

Procedure

1. Optional: View your current qdisc.

   # tc qdisc show dev enp0s1

2. Inspect the current qdisc counters.

   # tc -s qdisc show dev enp0s1
   qdisc fq_codel 0: root refcnt 2 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
   Sent 1008193 bytes 5559 pkt (dropped 233, overlimits 55 requeues 77)
   backlog 0b 0p requeues 0
   ....

Procedure

1. View the current default qdisc.

   # sysctl -a | grep qdisc
   net.core.default_qdisc = fq_codel

2. View the qdisc of current Ethernet connection.

   # tc -s qdisc show dev enp0s1
   qdisc fq_codel 0: root refcnt 2 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
   Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
   backlog 0b 0p requeues 0
   maxpacket 0 drop_overlimit 0 new_flow_count 0 ecn_mark 0
   new_flows_len 0 old_flows_len 0

3. Update the existing qdisc.

   # sysctl -w net.core.default_qdisc=pfifo_fast

4. To apply the changes, reload the network driver.

   # rmmod NETWORKDRIVERNAME

   # modprobe NETWORKDRIVERNAME

5. Start the network interface.

   # ip link set enp0s1 up

Procedure

1. Optional: View the current qdisc.

   # tc -s qdisc show dev enp0s1

2. Update the current qdisc.

   # tc qdisc replace dev enp0s1 root htb

Procedure

1. To start nmtui, enter:

   # nmtui

   

2. To navigate:

   • Use the cursors or press Tab to step forwards and press Shift+Tab to step back through the options.
   • Use Enter to select an option.
   • Use the Space bar to toggle the status of check boxes.

Procedure

1. Start the NetworkManager text user interface utility:

   # nmtui

2. Select the Edit a connection menu entry, and press Enter.
3. Select the Add button, and press Enter.
4. Select Ethernet, and press Enter.

5. Fill the fields with the connection details.

   
6. Select OK to save the changes.
7. Select Back to return to the main menu.
8. Select Activate a connection, and press Enter.
9. Select the new connection entry, and press Enter to activate the connection.
10. Select Back to return to the main menu.
11. Select Quit.

Verification steps

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp1s0      ethernet  connected  Example-Connection

2. To display all settings of the connection profile:

   # nmcli connection show Example-Connection
   connection.id:              Example-Connection
   connection.uuid:            b6cdfa1c-e4ad-46e5-af8b-a75f06b79f76
   connection.stable-id:       --
   connection.type:            802-3-ethernet
   connection.interface-name:  enp1s0
   ...

Procedure

1. In the main menu, select the Activate a connection menu entry:

   
2. Select the modified connection.

3. On the right, select the Deactivate button, and press Enter:

   
4. Select the connection again.

5. On the right, select the Activate button, and press Enter:

   

Procedure

1. Click the network connection icon in the top right corner of your desktop.

   

2. Depending on the connection type, select the Wired or Wi-Fi entry.

   
   • For a wired connection, select Connect to connect to the network.
   • For a Wi-Fi connection, click Select network, select the network to which you want to connect, and enter the password.

Procedure

1. Add a new NetworkManager connection profile for the Ethernet connection:

   # nmcli connection add con-name Example-Connection ifname enp7s0 type ethernet

   The further steps modify the Example-Connection connection profile you created.

2. Set the IPv4 address:

   # nmcli connection modify Example-Connection ipv4.addresses 192.0.2.1/24

3. Set the IPv6 address:

   # nmcli connection modify Example-Connection ipv6.addresses 2001:db8:1::1/64

4. Set the IPv4 and IPv6 connection method to manual:

   # nmcli connection modify Example-Connection ipv4.method manual
   # nmcli connection modify Example-Connection ipv6.method manual

5. Set the IPv4 and IPv6 default gateways:

   # nmcli connection modify Example-Connection ipv4.gateway 192.0.2.254
   # nmcli connection modify Example-Connection ipv6.gateway 2001:db8:1::fffe

6. Set the IPv4 and IPv6 DNS server addresses:

   # nmcli connection modify Example-Connection ipv4.dns "192.0.2.200"
   # nmcli connection modify Example-Connection ipv6.dns "2001:db8:1::ffbb"

   To set multiple DNS servers, specify them space-separated and enclosed in quotes.

7. Set the DNS search domain for the IPv4 and IPv6 connection:

   # nmcli connection modify Example-Connection ipv4.dns-search example.com
   # nmcli connection modify Example-Connection ipv6.dns-search example.com

8. Activate the connection profile:

   # nmcli connection up Example-Connection
   Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/13)

Verification steps

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  Example-Connection

2. To display all settings of the connection profile:

   # nmcli connection show Example-Connection
   connection.id:              Example-Connection
   connection.uuid:            b6cdfa1c-e4ad-46e5-af8b-a75f06b79f76
   connection.stable-id:       --
   connection.type:            802-3-ethernet
   connection.interface-name:  enp7s0
   ...

3. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet.

     For IPv4:

     # ping 192.0.2.3

     For IPv6:

     # ping 2001:db8:2::1

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet.

     For IPv4:

     # ping 198.162.3.1

     For IPv6:

     # ping 2001:db8:2::1

     • If the command fails, ping the default gateway to verify settings.

       For IPv4:

       # ping 192.0.2.254

       For IPv6:

       # ping 2001:db8:1::fffe

4. Use the host utility to verify that name resolution works. For example:

   # host client.example.com

   If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Troubleshooting steps

1. If the connection fails or if the network interface switches between an up and down status:

   • Make sure that the network cable is plugged-in to the host and a switch.
   • Check whether the link failure exists only on this host or also on other hosts connected to the same switch the server is connected to.
   • Verify that the network cable and the network interface are working as expected. Perform hardware diagnosis steps and replace defect cables and network interface cards.

Procedure

1. To add a new NetworkManager connection profile for the Ethernet connection, and starting the interactive mode, enter:

   # nmcli connection edit type ethernet con-name Example-Connection

2. Set the network interface:

   nmcli> set connection.interface-name enp7s0

3. Set the IPv4 address:

   nmcli> set ipv4.addresses 192.0.2.1/24

4. Set the IPv6 address:

   nmcli> set ipv6.addresses 2001:db8:1::1/64

5. Set the IPv4 and IPv6 connection method to manual:

   nmcli> set ipv4.method manual
   nmcli> set ipv6.method manual

6. Set the IPv4 and IPv6 default gateways:

   nmcli> set ipv4.gateway 192.0.2.254
   nmcli> set ipv6.gateway 2001:db8:1::fffe

7. Set the IPv4 and IPv6 DNS server addresses:

   nmcli> set ipv4.dns 192.0.2.200
   nmcli> set ipv6.dns 2001:db8:1::ffbb

   To set multiple DNS servers, specify them space-separated and enclosed in quotes.

8. Set the DNS search domain for the IPv4 and IPv6 connection:

   nmcli> set ipv4.dns-search example.com
   nmcli> set ipv6.dns-search example.com

9. Save and activate the connection:

   nmcli> save persistent
   Saving the connection with 'autoconnect=yes'. That might result in an immediate activation of the connection.
   Do you still want to save? (yes/no) [yes] yes

10. Leave the interactive mode:

    nmcli> quit

Verification steps

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  Example-Connection

2. To display all settings of the connection profile:

   # nmcli connection show Example-Connection
   connection.id:              Example-Connection
   connection.uuid:            b6cdfa1c-e4ad-46e5-af8b-a75f06b79f76
   connection.stable-id:       --
   connection.type:            802-3-ethernet
   connection.interface-name:  enp7s0
   ...

3. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet.

     For IPv4:

     # ping 192.0.2.3

     For IPv6:

     # ping 2001:db8:2::1

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet.

     For IPv4:

     # ping 198.162.3.1

     For IPv6:

     # ping 2001:db8:2::1

     • If the command fails, ping the default gateway to verify settings.

       For IPv4:

       # ping 192.0.2.254

       For IPv6:

       # ping 2001:db8:1::fffe

4. Use the host utility to verify that name resolution works. For example:

   # host client.example.com

   If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Troubleshooting steps

1. If the connection fails or if the network interface switches between an up and down status:

   • Make sure that the network cable is plugged-in to the host and a switch.
   • Check whether the link failure exists only on this host or also on other hosts connected to the same switch the server is connected to.
   • Verify that the network cable and the network interface are working as expected. Perform hardware diagnosis steps and replace defect cables and network interface cards.

Procedure

1. If the host on which you want to execute the instructions in the playbook is not inventoried yet, add the IP or name of this host to the /etc/ansible/hosts Ansible inventory file:

   node.example.com

2. Create the ~/ethernet-static-IP.yml playbook with the following content:

   ---
   - name: Configure an Ethernet connection with static IP
     hosts: node.example.com
     become: true
     tasks:
     - include_role:
         name: linux-system-roles.network
   
       vars:
         network_connections:
           - name: enp7s0
             type: ethernet
             autoconnect: yes
             ip:
               address:
                 - 192.0.2.1/24
                 - 2001:db8:1::1/64
               gateway4: 192.0.2.254
               gateway6: 2001:db8:1::fffe
               dns:
                 - 192.0.2.200
                 - 2001:db8:1::ffbb
               dns_search:
                 - example.com
             state: up

3. Run the playbook:

   • To connect as root user to the managed host, enter:

     # ansible-playbook -u root ~/ethernet-static-IP.yml

   • To connect as a user to the managed host, enter:

     # ansible-playbook -u user_name --ask-become-pass ~/ethernet-static-IP.yml

     The --ask-become-pass option defines that ansible-playbook command prompts for the sudo password of the user defined in the -u user_name option.

   If you do not specify the -u user_name option, ansible-playbook connects to the managed host as the user that is currently logged in to the control node.

Procedure

1. Add a new NetworkManager connection profile for the Ethernet connection:

   # nmcli connection add con-name Example-Connection ifname enp7s0 type ethernet

2. Optionally, change the host name NetworkManager sends to the DHCP server when using the Example-Connection profile:

   # nmcli connection modify Example-Connection ipv4.dhcp-hostname Example ipv6.dhcp-hostname Example

3. Optionally, change the client ID NetworkManager sends to an IPv4 DHCP server when using the Example-Connection profile:

   # nmcli connection modify Example-Connection ipv4.dhcp-client-id client-ID

   Note that there is no dhcp-client-id parameter for IPv6. To create an identifier for IPv6, configure the dhclient service.

Verification steps

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  Example-Connection

2. To display all settings of the connection profile:

   # nmcli connection show Example-Connection
   connection.id:              Example-Connection
   connection.uuid:            b6cdfa1c-e4ad-46e5-af8b-a75f06b79f76
   connection.stable-id:       --
   connection.type:            802-3-ethernet
   connection.interface-name:  enp7s0
   ...

3. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet.

     For IPv4:

     # ping 192.0.2.3

     For IPv6:

     # ping 2001:db8:2::1

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet.

     For IPv4:

     # ping 198.162.3.1

     For IPv6:

     # ping 2001:db8:2::1

     • If the command fails, ping the default gateway to verify settings.

       For IPv4:

       # ping 192.0.2.254

       For IPv6:

       # ping 2001:db8:1::fffe

4. Use the host utility to verify that name resolution works. For example:

   # host client.example.com

   If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Procedure

1. To add a new NetworkManager connection profile for the Ethernet connection, and starting the interactive mode, enter:

   # nmcli connection edit type ethernet con-name Example-Connection

2. Set the network interface:

   nmcli> set connection.interface-name enp7s0

3. Optionally, change the host name NetworkManager sends to the DHCP server when using the Example-Connection profile:

   nmcli> set ipv4.dhcp-hostname Example
   nmcli> set ipv6.dhcp-hostname Example

4. Optionally, change the client ID NetworkManager sends to an IPv4 DHCP server when using the Example-Connection profile:

   nmcli> set ipv4.dhcp-client-id client-ID

   Note that there is no dhcp-client-id parameter for IPv6. To create an identifier for IPv6, configure the dhclient service.

5. Save and activate the connection:

   nmcli> save persistent
   Saving the connection with 'autoconnect=yes'. That might result in an immediate activation of the connection.
   Do you still want to save? (yes/no) [yes] yes

6. Leave the interactive mode:

   nmcli> quit

Verification steps

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  Example-Connection

2. To display all settings of the connection profile:

   # nmcli connection show Example-Connection
   connection.id:              Example-Connection
   connection.uuid:            b6cdfa1c-e4ad-46e5-af8b-a75f06b79f76
   connection.stable-id:       --
   connection.type:            802-3-ethernet
   connection.interface-name:  enp7s0
   ...

3. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet.

     For IPv4:

     # ping 192.0.2.3

     For IPv6:

     # ping 2001:db8:2::1

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet.

     For IPv4:

     # ping 198.162.3.1

     For IPv6:

     # ping 2001:db8:2::1

     • If the command fails, ping the default gateway to verify settings.

       For IPv4:

       # ping 192.0.2.254

       For IPv6:

       # ping 2001:db8:1::fffe

4. Use the host utility to verify that name resolution works. For example:

   # host client.example.com

   If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Procedure

1. If the host on which you want to execute the instructions in the playbook is not inventoried yet, add the IP or name of this host to the /etc/ansible/hosts Ansible inventory file:

   node.example.com

2. Create the ~/ethernet-dynamic-IP.yml playbook with the following content:

   ---
   - name: Configure an Ethernet connection with dynamic IP
     hosts: node.example.com
     become: true
     tasks:
     - include_role:
         name: linux-system-roles.network
   
       vars:
         network_connections:
           - name: enp7s0
             type: ethernet
             autoconnect: yes
             ip:
               dhcp4: yes
               auto6: yes
             state: up

3. Run the playbook:

   • To connect as root user to the managed host, enter:

     # ansible-playbook -u root ~/ethernet-dynamic-IP.yml

   • To connect as a user to the managed host, enter:

     # ansible-playbook -u user_name --ask-become-pass ~/ethernet-dynamic-IP.yml

     The --ask-become-pass option defines that ansible-playbook command prompts for the sudo password of the user defined in the -u user_name option.

   If you do not specify the -u user_name option, ansible-playbook connects to the managed host as the user that is currently logged in to the control node.

Procedure

1. Press the Super key, enter Settings, and press Enter.
2. Select Network in the navigation on the left.
3. Click the + button next to the Wired entry to create a new profile.
4. Optional: Set a name for the connection on the Identity tab.

5. On the IPv4 tab, configure the IPv4 settings. For example, select method Manual, set a static IPv4 address, network mask, default gateway, and DNS server:

   

6. On the IPv6 tab, configure the IPv6 settings. For example, select method Manual, set a static IPv6 address, network mask, default gateway, and DNS server:

   
7. Click the Add button to save the connection. The GNOME control-center automatically activates the connection.

Verification steps

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  Example-Connection

2. To display all settings of the connection profile:

   # nmcli connection show Example-Connection
   connection.id:              Example-Connection
   connection.uuid:            b6cdfa1c-e4ad-46e5-af8b-a75f06b79f76
   connection.stable-id:       --
   connection.type:            802-3-ethernet
   connection.interface-name:  enp7s0
   ...

3. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet.

     For IPv4:

     # ping 192.0.2.3

     For IPv6:

     # ping 2001:db8:2::1

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet.

     For IPv4:

     # ping 198.162.3.1

     For IPv6:

     # ping 2001:db8:2::1

     • If the command fails, ping the default gateway to verify settings.

       For IPv4:

       # ping 192.0.2.254

       For IPv6:

       # ping 2001:db8:1::fffe

4. Use the host utility to verify that name resolution works. For example:

   # host client.example.com

   If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Troubleshooting steps

1. If the connection fails or if the network interface switches between an up and down status:

   • Make sure that the network cable is plugged-in to the host and a switch.
   • Check whether the link failure exists only on this host or also on other hosts connected to the same switch the server is connected to.
   • Verify that the network cable and the network interface are working as expected. Perform hardware diagnosis steps and replace defect cables and network interface cards.

Procedure

1. Open a terminal, and enter:

   $ nm-connection-editor

2. Click the + button to add a new connection.
3. Select the Ethernet connection type, and click Create.

4. On the General tab:

   1. To automatically enable this connection when the system boots or when you restart the NetworkManager service:

      1. Select Connect automatically with priority.

      2. Optional: Change the priority value next to Connect automatically with priority.

         If multiple connection profiles exist for the same device, NetworkManager enables only one profile. By default, NetworkManager activates the last-used profile that has auto-connect enabled. However, if you set priority values in the profiles, NetworkManager activates the profile with the highest priority.

   2. Clear the All users may connect to this network check box if the profile should be available only to the user that created the connection profile.

   

5. On the Ethernet tab, select a device and, optionally, further Ethernet-related settings.
6. On the IPv4 Settings tab, configure the IPv4 settings. For example, set a static IPv4 address, network mask, default gateway, and DNS server:
7. On the IPv6 Settings tab, configure the IPv6 settings. For example, set a static IPv6 address, network mask, default gateway, and DNS server:
8. Save the connection.
9. Close nm-connection-editor.

Verification steps

1. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet.

     For IPv4:

     # ping 192.0.2.3

     For IPv6:

     # ping 2001:db8:2::1

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet.

     For IPv4:

     # ping 198.162.3.1

     For IPv6:

     # ping 2001:db8:2::1

     • If the command fails, ping the default gateway to verify settings.

       For IPv4:

       # ping 192.0.2.254

       For IPv6:

       # ping 2001:db8:1::fff3

   • Use the host utility to verify that name resolution works. For example:

     # host client.example.com

     If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Procedure

1. Set the ipv4.dhcp-timeout and ipv6.dhcp-timeout properties. For example, to set both options to 30 seconds, enter:

   # nmcli connection modify connection_name ipv4.dhcp-timeout 30 ipv6.dhcp-timeout 30

   Alternatively, set the parameters to infinity to configure that NetworkManager does not stop trying to request and renew an IP address until it is successful.

2. Optional: Configure the behavior if NetworkManager does not receive an IPv4 address before the timeout:

   # nmcli connection modify connection_name ipv4.may-fail value

   If you set the ipv4.may-fail option to:

   • yes, the status of the connection depends on the IPv6 configuration:

     • If the IPv6 configuration is enabled and successful, NetworkManager activates the IPv6 connection and no longer tries to activate the IPv4 connection.
     • If the IPv6 configuration is disabled or not configured, the connection fails.

   • no, the connection is deactivated. In this case:

     • If the autoconnect property of the connection is enabled, NetworkManager retries to activate the connection as many times as set in the autoconnect-retries property. The default is 4.
     • If the connection still cannot acquire a DHCP address, auto-activation fails. Note that after 5 minutes, the auto-connection process starts again to acquire an IP address from the DHCP server.

3. Optional: Configure the behavior if NetworkManager does not receive an IPv6 address before the timeout:

   # nmcli connection modify connection_name ipv6.may-fail value

Procedure

1. To create a Wi-Fi connection profile with static IP configuration:

   ~]$ nmcli con add con-name MyCafe ifname wlan0 type wifi ssid MyCafe ` `ip4 192.168.100.101/24 gw4 192.168.100.1

2. Set a DNS server. For example, to set 192.160.100.1 as the DNS server:

   ~]$ nmcli con modify con-name MyCafe ipv4.dns "192.160.100.1"

3. Optionally, set a DNS search domain. For example, to set the search domain to example.com:

   ~]$ nmcli con modify con-name MyCafe ipv4.dns-search "example.com"

4. To check a specific property, for example mtu:

   ~]$ nmcli connection show id MyCafe | grep mtu
   802-11-wireless.mtu:                     auto

5. To change the property of a setting:

   ~]$ nmcli connection modify id MyCafe 802-11-wireless.mtu 1350

6. To verify the change:

   ~]$ nmcli connection show id MyCafe | grep mtu
   802-11-wireless.mtu:                     1350

Verification steps

1. Use the ping utility to verify that this host can send packets to other hosts.

   • Ping an IP address in the same subnet. For example:

     # ping 192.168.100.103

     If the command fails, verify the IP and subnet settings.

   • Ping an IP address in a remote subnet. For example:

     # ping 198.51.16.3

     • If the command fails, ping the default gateway to verify settings.

       # ping 192.168.100.1

2. Use the host utility to verify that name resolution works. For example:

   # host client.example.com

   If the command returns any error, such as connection timed out or no servers could be reached, verify your DNS settings.

Procedure

1. Press the Super key to enter the Activities Overview, type Wi-Fi and press Enter. In the left-hand-side menu entry you see the list of available networks.

2. Select the gear wheel icon to the right of the Wi-Fi connection name that you want to edit, and the editing connection dialog appears. The Details menu window shows the connection details where you can make further configuration.

   Options

   1. If you select Connect automatically, NetworkManager auto-connects to this connection whenever NetworkManager detects that it is available. If you do not want NetworkManager to connect automatically, clear the check box. Note that when the check box is clear, you have to select that connection manually in the network connection icon’s menu to cause it to connect.
   2. To make a connection available to other users, select the Make available to other users check box.

   3. You can also control the background data usage. If you leave Restrict background data usage unspecified (default), then NetworkManager tries to download data that you are actively using. Otherwise, select the check box and NetworkManager sets the connection as metered, and applies restriction on the background data usage.

      Note

      To delete a Wi-Fi connection, click the Forget Connection red box.

3. Select the Identity menu entry to see the basic configuration options.

   SSID — The Service Set Identifier (SSID) of the access point (AP).

   BSSID — The Basic Service Set Identifier (BSSID) is the MAC address, also known as a hardware address, of the specific wireless access point you are connecting to when in Infrastructure mode. This field is blank by default, and you are able to connect to a wireless access point by SSID without having to specify its BSSID. If the BSSID is specified, it will force the system to associate to a specific access point only. For ad-hoc networks, the BSSID is generated randomly by the mac80211 subsystem when the ad-hoc network is created. It is not displayed by NetworkManager.

   MAC address — The MAC address allows you to associate a specific wireless adapter with a specific connection (or connections).

   Cloned Address — A cloned MAC address to use in place of the real hardware address. Leave blank unless required.

4. For further IP address configuration , select the IPv4 and IPv6 menu entries.

   By default, both IPv4 and IPv6 are set to automatic configuration depending on current network settings. This means that addresses such as the local IP address, DNS address, and other settings will be detected automatically when the interface connects to a network. If a DHCP server assigns the IP configuration in this network, this is sufficient, but you can also provide static configuration in the IPv4 and IPv6 Settings. In the IPv4 and IPv6 menu entries, you can see the following settings:

   • IPv4 Method

     • Automatic (DHCP) — Choose this option if the network you are connecting to uses Router Advertisements (RA) or a DHCP server to assign dynamic IP addresses. You can see the assigned IP address in the Details menu entry.
     • Link-Local Only — Choose this option if the network you are connecting to does not have a DHCP server and you do not want to assign IP addresses manually. Random addresses will be assigned as per RFC 3927 with prefix 169.254/16.
     • Manual — Choose this option if you want to assign IP addresses manually.
     • Disable — IPv4 is disabled for this connection.

   • DNS

     If Automatic is ON, and no DHCP server is available that assigns DNS servers to this connection, switch it to OFF to enter the IP address of a DNS server separating the IPs by comma.

   • Routes

     Note that in the Routes section, when Automatic is ON, routes from Router Advertisements (RA) or DHCP are used, but you can also add additional static routes. When OFF, only static routes are used.

     • Address — Enter the IP address of a remote network, sub-net, or host.
     • Netmask — The netmask or prefix length of the IP address entered above.
     • Gateway — The IP address of the gateway leading to the remote network, sub-net, or host entered above.
     • Metric — A network cost, a preference value to give to this route. Lower values will be preferred over higher values.

   • Use this connection only for resources on its network

     Select this check box to prevent the connection from becoming the default route.

     Alternatively, to configure IPv6 settings in a Wi-Fi connection, select the IPv6 menu entry:

   • IPv6 Method

     • Automatic — Choose this option to use IPv6 Stateless Address AutoConfiguration (SLAAC) to create an automatic, stateless configuration based on the hardware address and Router Advertisements (RA).
     • Automatic, DHCP only — Choose this option to not use RA, but request information from DHCPv6 directly to create a stateful configuration.
     • Link-Local Only — Choose this option if the network you are connecting to does not have a DHCP server and you do not want to assign IP addresses manually. Random addresses will be assigned as per RFC 4862 with prefix FE80::0.
     • Manual — Choose this option if you want to assign IP addresses manually.
     • Disable — IPv6 is disabled for this connection.
   • The DNS, Routes, Use this connection only for resources on its network fields are common to IPv4 settings.

5. To configure Security settings in a Wi-Fi connection, select the Security menu entry. The following configuration options are available:

   • Security

     • None — Do not encrypt the Wi-Fi connection.
     • WEP 40/128-bit Key — Wired Equivalent Privacy (WEP), from the IEEE 802.11 standard. Uses a single pre-shared key (PSK).

     • WEP 128-bit Passphrase — An MD5 hash of the passphrase to derive a WEP key.

       Warning

       If the Wi-Fi use no encryption, WEP, or WPA, do not use the network because it is insecure and everyone can read the data you send over this network.

     • LEAP — Lightweight Extensible Authentication Protocol, from Cisco Systems.
     • Dynamic WEP (802.1X) — WEP keys are changed dynamically.
     • WPA & WPA2 Personal — Wi-Fi Protected Access (WPA), from the draft IEEE 802.11i standard. A replacement for WEP. Wi-Fi Protected Access II (WPA2), from the 802.11i-2004 standard. Personal mode uses a pre-shared key (WPA-PSK).
     • WPA & WPA2 Enterprise — WPA for use with a RADIUS authentication server to provide IEEE 802.1X network access control.
   • Password — Enter the password to be used in the authentication process.
6. Once you have finished the configuration, click the Apply button to save it.

Procedure

1. To refresh the available Wi-Fi connection list:

   ~]$ nmcli device wifi rescan

2. To view the available Wi-Fi access points:

   ~]$ nmcli dev wifi list
   
   IN-USE  SSID      MODE   CHAN  RATE        SIGNAL  BARS  SECURITY
   ...
           MyCafe    Infra  3     405 Mbit/s  85      ▂▄▆█  WPA1 WPA2

3. To connect to a Wi-Fi connection using nmcli:

   ~]$ nmcli dev wifi connect SSID-Name password wireless-password

   For example:

   ~]$ nmcli dev wifi connect MyCafe password wireless-password

   Note that if you want to disable the Wi-Fi state:

   ~]$ nmcli radio wifi off

Procedure

1. Open the GNOME Shell network connection icon menu from the top right-hand corner of the screen.
2. Select Wi-Fi Not Connected.
3. Click the Select Network option.

4. Click the name of the network to which you want to connect, and then click Connect.

   Note that if you do not see the network, the network might be hidden.

5. If the network is protected by a password or encryption keys are required, enter the password and click Connect.

   Note that if you do not know the password, contact the administrator of the Wi-Fi network.

6. If the connection is successful, the name of the network is visible in the connection icon menu and the wireless indicator is on the top right-hand corner of the screen.

Prerequisites

1. The network must have 802.1X network authentication.
2. The Ethernet connection profile exists in NetworkManager and has a valid IP configuration.
3. If the client is required to verify the certificate of the authenticator, the Certificate Authority (CA) certificate must be stored in the /etc/pki/ca-trust/source/anchors/ directory.
4. The wpa_supplicant package is installed.

Procedure

1. Set the Extensible Authentication Protocol (EAP) to peap, the inner authentication protocol to mschapv2, and the user name:

   # nmcli connection modify enp1s0 802-1x.eap peap 802-1x.phase2-auth mschapv2 802-1x.identity user_name

   Note that you must set the 802-1x.eap, 802-1x.phase2-auth, and 802-1x.identity parameters in a single command.

2. Optionally, store the password in the configuration:

   # nmcli connection modify enp1s0 802-1x.password password

   Important

   By default, NetworkManager stores the password in clear text in the /etc/sysconfig/network-scripts/keys-connection_name file, that is readable only by the root user. However, clear text passwords in a configuration file can be a security risk.

   To increase the security, set the 802-1x.password-flags parameter to 0x1. With this setting, on servers with the GNOME desktop environment or the nm-applet running, NetworkManager retrieves the password from these services. In other cases, NetworkManager prompts for the password.

3. If the client is required to verify the certificate of the authenticator, set the 802-1x.ca-cert parameter in the connection profile to the path of the CA certificate:

   # nmcli connection modify enp1s0 802-1x.ca-cert /etc/pki/ca-trust/source/anchors/ca.crt

   Note

   For security reasons, Red Hat recommends using the certificate of the authenticator to enable clients to validate the identity of the authenticator.

4. Activate the connection profile:

   # nmcli connection up enp1s0

Procedure

1. If the host on which you want to execute the instructions in the playbook is not inventoried yet, add the IP address or name of the host to the /etc/ansible/hosts Ansible inventory file:

   node.example.com

2. Create the ~/enable-802.1x.yml playbook with the following content:

   ---
   - name: Configure an Ethernet connection with 802.1X authentication
     hosts: node.example.com
     become: true
     tasks:
       - name: Copy client key for 802.1X authentication
         copy:
           src: "/srv/data/client.key"
           dest: "/etc/pki/tls/private/client.key"
           mode: 0600
   
       - name: Copy client certificate for 802.1X authentication
         copy:
           src: "/srv/data/client.crt"
           dest: "/etc/pki/tls/certs/client.crt"
   
       - name: Copy CA certificate for 802.1X authentication
         copy:
           src: "/srv/data/ca.crt"
           dest: "/etc/pki/ca-trust/source/anchors/ca.crt"
   
       - include_role:
           name: linux-system-roles.network
         vars:
           network_connections:
             - name: enp1s0
               type: ethernet
               autoconnect: yes
               ip:
                 address:
                   - 192.0.2.1/24
                   - 2001:db8:1::1/64
                 gateway4: 192.0.2.254
                 gateway6: 2001:db8:1::fffe
                 dns:
                   - 192.0.2.200
                   - 2001:db8:1::ffbb
                 dns_search:
                   - example.com
               ieee802_1x:
                 identity: user_name
                 eap: tls
                 private_key: "/etc/pki/tls/private/client.key"
                 private_key_password: "password"
                 client_cert: "/etc/pki/tls/certs/client.crt"
                 ca_cert: "/etc/pki/ca-trust/source/anchors/ca.crt"
                 domain_suffix_match: example.com
               state: up

3. Run the playbook:

   • To connect as root user to the managed host, enter:

     # ansible-playbook -u root ~/enable-802.1x.yml

   • To connect as a user to the managed host, enter:

     # ansible-playbook -u user_name --ask-become-pass ~/ethernet-static-IP.yml

     The --ask-become-pass option defines that ansible-playbook command prompts for the sudo password of the user defined by the -u user_name option.

   If you do not specify the -u user_name option, ansible-playbook connects to the managed host as the user that is currently logged in to the control node.

Prerequisites

1. The network must have 802.1X network authentication.
2. The Wi-Fi connection profile exists in NetworkManager and has a valid IP configuration.
3. If the client is required to verify the certificate of the authenticator, the Certificate Authority (CA) certificate must be stored in the /etc/pki/ca-trust/source/anchors/ directory.
4. The wpa_supplicant package is installed.

Procedure

1. Set the Wi-Fi security mode to wpa-eap, the Extensible Authentication Protocol (EAP) to peap, the inner authentication protocol to mschapv2, and the user name:

   # nmcli connection modify wpl1s0 802-11-wireless-security.key-mgmt wpa-eap 802-1x.eap peap 802-1x.phase2-auth mschapv2 802-1x.identity user_name

   Note that you must set the 802-11-wireless-security.key-mgmt, 802-1x.eap, 802-1x.phase2-auth, and 802-1x.identity parameters in a single command.

2. Optionally, store the password in the configuration:

   # nmcli connection modify wpl1s0 802-1x.password password

   Important

   By default, NetworkManager stores the password in clear text in the /etc/sysconfig/network-scripts/keys-connection_name file, that is readable only by the root user. However, clear text passwords in a configuration file can be a security risk.

   To increase the security, set the 802-1x.password-flags parameter to 0x1. With this setting, on servers with the GNOME desktop environment or the nm-applet running, NetworkManager retrieves the password from these services. In other cases, NetworkManager prompts for the password.

3. If the client is required to verify the certificate of the authenticator, set the 802-1x.ca-cert parameter in the connection profile to the path of the CA certificate:

   # nmcli connection modify wpl1s0 802-1x.ca-cert /etc/pki/ca-trust/source/anchors/ca.crt

   Note

   For security reasons, Red Hat recommends using the certificate of the authenticator to enable clients to validate the identity of the authenticator.

4. Activate the connection profile:

   # nmcli connection up wpl1s0

Procedure

1. Set the IP address of the default gateway.

   For example, to set the IPv4 address of the default gateway on the example connection to 192.0.2.1:

   $ sudo nmcli connection modify example ipv4.gateway "192.0.2.1"

   For example, to set the IPv6 address of the default gateway on the example connection to 2001:db8:1::1:

   $ sudo nmcli connection modify example ipv6.gateway "2001:db8:1::1"

2. Restart the network connection for changes to take effect. For example, to restart the example connection using the command line:

   $ sudo nmcli connection up example

   Warning

   All connections currently using this network connection are temporarily interrupted during the restart.

3. Optionally, verify that the route is active.

   To display the IPv4 default gateway:

   $ ip -4 route
   default via 192.0.2.1 dev example proto static metric 100

   To display the IPv6 default gateway:

   $ ip -6 route
   default via 2001:db8:1::1 dev example proto static metric 100 pref medium

Procedure

1. Open the nmcli interactive mode for the required connection. For example, to open the nmcli interactive mode for the example connection:

   $ sudo nmcli connection edit example

2. Set the default gateway.

   For example, to set the IPv4 address of the default gateway on the example connection to 192.0.2.1:

   nmcli> set ipv4.gateway 192.0.2.1

   For example, to set the IPv6 address of the default gateway on the example connection to 2001:db8:1::1:

   nmcli> set ipv6.gateway 2001:db8:1::1

3. Optionally, verify that the default gateway was set correctly:

   nmcli> print
   ...
   ipv4.gateway:                           192.0.2.1
   ...
   ipv6.gateway:                           2001:db8:1::1
   ...

4. Save the configuration:

   nmcli> save persistent

5. Restart the network connection for changes to take effect:

   nmcli> activate example

   Warning

   All connections currently using this network connection are temporarily interrupted during the restart.

6. Leave the nmcli interactive mode:

   nmcli> quit

7. Optionally, verify that the route is active.

   To display the IPv4 default gateway:

   $ ip -4 route
   default via 192.0.2.1 dev example proto static metric 100

   To display the IPv6 default gateway:

   $ ip -6 route
   default via 2001:db8:1::1 dev example proto static metric 100 pref medium

Procedure

1. Open a terminal, and enter nm-connection-editor:

   $ nm-connection-editor

2. Select the connection to modify, and click the gear wheel icon to edit the existing connection.

3. Set the IPv4 default gateway. For example, to set the IPv4 address of the default gateway on the connection to 192.0.2.1:

   1. Open the IPv4 Settings tab.

   2. Enter the address in the gateway field next to the IP range the gateway’s address is within:

      

4. Set the IPv6 default gateway. For example, to set the IPv6 address of the default gateway on the connection to 2001:db8:1::1:

   1. Open the IPv6 tab.

   2. Enter the address in the gateway field next to the IP range the gateway’s address is within:

      

5. Click OK.
6. Click Save.

7. Restart the network connection for changes to take effect. For example, to restart the example connection using the command line:

   $ sudo nmcli connection up example

   Warning

   All connections currently using this network connection are temporarily interrupted during the restart.

8. Optionally, verify that the route is active.

   To display the IPv4 default gateway:

   $ ip -4 route
   default via 192.0.2.1 dev example proto static metric 100

   To display the IPv6 default gateway:

   $ ip -6 route
   default via 2001:db8:1::1 dev example proto static metric 100 pref medium

Procedure

1. Set the IPv4 default gateway. For example, to set the IPv4 address of the default gateway on the connection to 192.0.2.1:

   1. Open the IPv4 tab.

   2. Enter the address in the gateway field next to the IP range the gateway’s address is within:

      

2. Set the IPv6 default gateway. For example, to set the IPv6 address of the default gateway on the connection to 2001:db8:1::1:

   1. Open the IPv6 tab.

   2. Enter the address in the gateway field next to the IP range the gateway’s address is within:

      

3. Click Apply.

4. Back in the Network window, disable and re-enable the connection by switching the button for the connection to Off and back to On for changes to take effect.

   Warning

   All connections currently using this network connection are temporarily interrupted during the restart.

5. Optionally, verify that the route is active.

   To display the IPv4 default gateway:

   $ ip -4 route
   default via 192.0.2.1 dev example proto static metric 100

   To display the IPv6 default gateway:

   $ ip -6 route
   default via 2001:db8:1::1 dev example proto static metric 100 pref medium

Procedure

1. Set the GATEWAY parameter in the /etc/sysconfig/network-scripts/ifcfg-enp1s0 file to 192.0.2.1:

   GATEWAY=192.0.2.1

2. Add the default entry in the /etc/sysconfig/network-scripts/route-enp0s1 file:

   default via 192.0.2.1

3. Restart the network:

   # systemctl restart network

Procedure

1. Add the static route to the example connection:

   $ sudo nmcli connection modify example +ipv4.routes "192.0.2.0/24 198.51.100.1"

   To set multiple routes in one step, pass the individual routes comma-separated to the command. For example, to add a route to the 192.0.2.0/24 and 203.0.113.0/24 networks, both routed through the 198.51.100.1 gateway, enter:

   $ sudo nmcli connection modify example +ipv4.routes "192.0.2.0/24 198.51.100.1, 203.0.113.0/24 198.51.100.1"

2. Optionally, verify that the routes were added correctly to the configuration:

   $ nmcli connection show example
   ...
   ipv4.routes:        { ip = 192.0.2.1/24, nh = 198.51.100.1 }
   ...

3. Restart the network connection:

   $ sudo nmcli connection up example

   Warning

   Restarting the connection briefly disrupts connectivity on that interface.

4. Optionally, verify that the route is active:

   $ ip route
   ...
   192.0.2.0/24 via 198.51.100.1 dev example proto static metric 100

Procedure

1. Open the IPv4 tab.
2. Optionally, disable automatic routes by clicking the On button in the Routes section of the IPv4 tab to use only static routes. If automatic routes are enabled, Red Hat Enterprise Linux uses static routes and routes received from a DHCP server.

3. Enter the address, netmask, gateway, and optionally a metric value:

   

4. Click Apply.

5. Back in the Network window, disable and re-enable the connection by switching the button for the connection to Off and back to On for changes to take effect.

   Warning

   Restarting the connection briefly disrupts connectivity on that interface.

6. Optionally, verify that the route is active:

   $ ip route
   ...
   192.0.2.0/24 via 198.51.100.1 dev example proto static metric 100

Procedure

1. Open a terminal and enter nm-connection-editor:

   $ nm-connection-editor

2. Select the example connection and click the gear wheel icon to edit the existing connection.
3. Open the IPv4 tab.
4. Click the Routes button.

5. Click the Add button and enter the address, netmask, gateway, and optionally a metric value.

   

6. Click OK.
7. Click Save.

8. Restart the network connection for changes to take effect. For example, to restart the example connection using the command line:

   $ sudo nmcli connection up example

9. Optionally, verify that the route is active:

   $ ip route
   ...
   192.0.2.0/24 via 198.51.100.1 dev example proto static metric 100

Procedure

1. Open the nmcli interactive mode for the example connection:

   $ sudo nmcli connection edit example

2. Add the static route:

   nmcli> set ipv4.routes 192.0.2.0/24 198.51.100.1

3. Optionally, verify that the routes were added correctly to the configuration:

   nmcli> print
   ...
   ipv4.routes:        { ip = 192.0.2.1/24, nh = 198.51.100.1 }
   ...

   The ip attribute displays the network to route and the nh attribute the gateway (next hop).

4. Save the configuration:

   nmcli> save persistent

5. Restart the network connection:

   nmcli> activate example

   Warning

   When you restart the connection, all connections currently using this connection will be temporarily interrupted.

6. Leave the nmcli interactive mode:

   nmcli> quit

7. Optionally, verify that the route is active:

   $ ip route
   ...
   192.0.2.0/24 via 198.51.100.1 dev example proto static metric 100

Procedure

1. Add the static IPv4 route to the /etc/sysconfig/network-scripts/route-enp0s1 file:

   ADDRESS0=192.0.2.0
   NETMASK0=255.255.255.0
   GATEWAY0=198.51.100.1

   • The ADDRESS0 variable defines the network of the first routing entry.
   • The NETMASK0 variable defines the netmask of the first routing entry.

   • The GATEWAY0 variable defines the IP address of the gateway to the remote network or host for the first routing entry.

     If you add multiple static routes, increase the number in the variable names. Note that the variables for each route must be numbered sequentially. For example, ADDRESS0, ADDRESS1, ADDRESS3, and so on.

2. Restart the network:

   # systemctl restart network

Procedure

1. Add the static IPv4 route to the /etc/sysconfig/network-scripts/route-enp0s1 file:

   192.0.2.0/24 via 198.51.100.1 dev enp0s1

2. Add the static IPv6 route to the /etc/sysconfig/network-scripts/route6-enp0s1 file:

   2001:db8:1::/64 via 2001:db8:2::1 dev enp0s1

3. Restart the network:

   # systemctl restart network

Procedure

1. Configure the network interface to provider A:

   # nmcli connection add type ethernet con-name Provider-A ifname enp7s0 ipv4.method manual ipv4.addresses 198.51.100.1/30 ipv4.gateway 198.51.100.2 ipv4.dns 198.51.100.200 connection.zone external

   The nmcli connection add command creates a NetworkManager connection profile. The following list describes the options of the command:

   • type ethernet: Defines that the connection type is Ethernet.
   • con-name connection_name: Sets the name of the profile. Use a meaningful name to avoid confusion.
   • ifname network_device: Sets the network interface.
   • ipv4.method manual: Enables to configure a static IP address.
   • ipv4.addresses IP_address/subnet_mask: Sets the IPv4 addresses and subnet mask.
   • ipv4.gateway IP_address: Sets the default gateway address.
   • ipv4.dns IP_of_DNS_server: Sets the IPv4 address of the DNS server.
   • connection.zone firewalld_zone: Assigns the network interface to the defined firewalld zone. Note that firewalld automatically enables masquerading for interfaces assigned to the external zone.

2. Configure the network interface to provider B:

   # nmcli connection add type ethernet con-name Provider-B ifname enp1s0 ipv4.method manual ipv4.addresses 192.0.2.1/30 ipv4.routes "0.0.0.0/1 192.0.2.2 table=5000, 128.0.0.0/1 192.0.2.2 table=5000" connection.zone external

   This command uses the ipv4.routes parameter instead of ipv4.gateway to set the default gateway. This is required to assign the default gateway for this connection to a different routing table (5000) than the default. NetworkManager automatically creates this new routing table when the connection is activated.

   Note

   The nmcli utility does not support using 0.0.0.0/0 for the default gateway in ipv4.gateway. To work around this problem, the command creates separate routes for both the 0.0.0.0/1 and 128.0.0.0/1 subnets, which covers also the full IPv4 address space.

3. Configure the network interface to the internal workstations subnet:

   # nmcli connection add type ethernet con-name Internal-Workstations ifname enp8s0 ipv4.method manual ipv4.addresses 10.0.0.1/24 ipv4.routes "10.0.0.0/24 src=192.0.2.1 table=5000" ipv4.routing-rules "priority 5 from 10.0.0.0/24 table 5000" connection.zone internal

   This command uses the ipv4.routes parameter to add a static route to the routing table with ID 5000. This static route for the 10.0.0.0/24 subnet uses the IP of the local network interface to provider B (192.0.2.1) as next hop.

   Additionally, the command uses the ipv4.routing-rules parameter to add a routing rule with priority 5 that routes traffic from the 10.0.0.0/24 subnet to table 5000. Low values have a high priority.

   Note that the syntax in the ipv4.routing-rules parameter is the same as in an ip route add command, except that ipv4.routing-rules always requires specifying a priority.

4. Configure the network interface to the server subnet:

   # nmcli connection add type ethernet con-name Servers ifname enp9s0 ipv4.method manual ipv4.addresses 203.0.113.1/24 connection.zone internal

Verification steps

1. On a RHEL host in the internal workstation subnet:

   1. Install the traceroute package:

      # yum install traceroute

   2. Use the traceroute utility to display the route to a host on the Internet:

      # traceroute redhat.com
      traceroute to redhat.com (209.132.183.105), 30 hops max, 60 byte packets
       1  10.0.0.1 (10.0.0.1)     0.337 ms  0.260 ms  0.223 ms
       2  192.0.2.1 (192.0.2.1)   0.884 ms  1.066 ms  1.248 ms
       ...

      The output of the command displays that the router sends packets over 192.0.2.1, which is the network of provider B.

2. On a RHEL host in the server subnet:

   1. Install the traceroute package:

      # yum install traceroute

   2. Use the traceroute utility to display the route to a host on the Internet:

      # traceroute redhat.com
      traceroute to redhat.com (209.132.183.105), 30 hops max, 60 byte packets
       1  203.0.113.1 (203.0.113.1)    2.179 ms  2.073 ms  1.944 ms
       2  198.51.100.2 (198.51.100.2)  1.868 ms  1.798 ms  1.549 ms
       ...

      The output of the command displays that the router sends packets over 198.51.100.2, which is the network of provider A.

1. Display the rule list:

   # ip rule list
   0:	from all lookup local
   5:	from 10.0.0.0/24 lookup 5000
   32766:	from all lookup main
   32767:	from all lookup default

   By default, RHEL contains rules for the tables local, main, and default.

2. Display the routes in table 5000:

   # ip route list table 5000
   0.0.0.0/1 via 192.0.2.2 dev enp1s0 proto static metric 100
   10.0.0.0/24 dev enp8s0 proto static scope link src 192.0.2.1 metric 102
   128.0.0.0/1 via 192.0.2.2 dev enp1s0 proto static metric 100

3. Display the interfaces and firewall zones:

   # firewall-cmd --get-active-zones
   external
     interfaces: enp1s0 enp7s0
   internal
     interfaces: enp8s0 enp9s0

4. Verify that the external zone has masquerading enabled:

   # firewall-cmd --info-zone=external
   external (active)
     target: default
     icmp-block-inversion: no
     interfaces: enp1s0 enp7s0
     sources:
     services: ssh
     ports:
     protocols:
     masquerade: yes
     ...

Procedure

1. Add the configuration for the network interface to provider A by creating the /etc/sysconfig/network-scripts/ifcfg-1_Provider-A file with the following content:

   TYPE=Ethernet
   IPADDR=198.51.100.1
   PREFIX=30
   GATEWAY=198.51.100.2
   DNS1=198.51.100.200
   DEFROUTE=yes
   NAME=1_Provider-A
   DEVICE=enp7s0
   ONBOOT=yes
   ZONE=external

   The following list describes the parameters used in the configuration file:

   • TYPE=Ethernet: Defines that the connection type is Ethernet.
   • IPADDR=IP_address: Sets the IPv4 address.
   • PREFIX=subnet_mask: Sets the subnet mask.
   • GATEWAY=IP_address: Sets the default gateway address.
   • DNS1=IP_of_DNS_server: Sets the IPv4 address of the DNS server.
   • DEFROUTE=yes|no: Defines whether the connection is a default route or not.
   • NAME=connection_name: Sets the name of the connection profile. Use a meaningful name to avoid confusion.
   • DEVICE=network_device: Sets the network interface.
   • ONBOOT=yes: Defines that RHEL starts this connection when the system boots.
   • ZONE=firewalld_zone: Assigns the network interface to the defined firewalld zone. Note that firewalld automatically enables masquerading for interfaces assigned to the external zone.

2. Add the configuration for the network interface to provider B:

   1. Create the /etc/sysconfig/network-scripts/ifcfg-2_Provider-B file with the following content:

      TYPE=Ethernet
      IPADDR=192.0.2.1
      PREFIX=30
      DEFROUTE=no
      NAME=2_Provider-B
      DEVICE=enp1s0
      ONBOOT=yes
      ZONE=external

      Note that the configuration file for this interface does not contain a default gateway setting.

   2. Assign the gateway for the 2_Provider-B connection to a separate routing table. Therefore, create the /etc/sysconfig/network-scripts/route-2_Provider-B file with the following content:

      0.0.0.0/0 via 192.0.2.2 table 5000

      This entry assigns the gateway and traffic from all subnets routed through this gateway to table 5000.

3. Create the configuration for the network interface to the internal workstations subnet:

   1. Create the /etc/sysconfig/network-scripts/ifcfg-3_Internal-Workstations file with the following content:

      TYPE=Ethernet
      IPADDR=10.0.0.1
      PREFIX=24
      DEFROUTE=no
      NAME=3_Internal-Workstations
      DEVICE=enp8s0
      ONBOOT=yes
      ZONE=internal

   2. Add the routing rule configuration for the internal workstation subnet. Therefore, create the /etc/sysconfig/network-scripts/rule-3_Internal-Workstations file with the following content:

      pri 5 from 10.0.0.0/24 table 5000

      This configuration defines a routing rule with priority 5 that routes all traffic from the 10.0.0.0/24 subnet to table 5000. Low values have a high priority.

   3. Create the /etc/sysconfig/network-scripts/route-3_Internal-Workstations file with the following content to add a static route to the routing table with ID 5000:

      10.0.0.0/24 via 192.0.2.1 table 5000

      This static route defines that RHEL sends traffic from the 10.0.0.0/24 subnet to the IP of the local network interface to provider B (192.0.2.1). This interface is to routing table 5000 and used as the next hop.

4. Add the configuration for the network interface to the server subnet by creating the /etc/sysconfig/network-scripts/ifcfg-4_Servers file with the following content:

   TYPE=Ethernet
   IPADDR=203.0.113.1
   PREFIX=24
   DEFROUTE=no
   NAME=4_Servers
   DEVICE=enp9s0
   ONBOOT=yes
   ZONE=internal

5. Restart the network:

   # systemctl restart network

Verification steps

1. On a RHEL host in the internal workstation subnet:

   1. Install the traceroute package:

      # yum install traceroute

   2. Use the traceroute utility to display the route to a host on the internet:

      # traceroute redhat.com
      traceroute to redhat.com (209.132.183.105), 30 hops max, 60 byte packets
       1  10.0.0.1 (10.0.0.1)     0.337 ms  0.260 ms  0.223 ms
       2  192.0.2.1 (192.0.2.1)   0.884 ms  1.066 ms  1.248 ms
       ...

      The output of the command displays that the router sends packets over 192.0.2.1, which is the network of provider B.

2. On a RHEL host in the server subnet:

   1. Install the traceroute package:

      # yum install traceroute

   2. Use the traceroute utility to display the route to a host on the internet:

      # traceroute redhat.com
      traceroute to redhat.com (209.132.183.105), 30 hops max, 60 byte packets
       1  203.0.113.1 (203.0.113.1)    2.179 ms  2.073 ms  1.944 ms
       2  198.51.100.2 (198.51.100.2)  1.868 ms  1.798 ms  1.549 ms
       ...

      The output of the command displays that the router sends packets over 198.51.100.2, which is the network of provider A.

1. Display the rule list:

   # ip rule list
   0:      from all lookup local
   5:      from 10.0.0.0/24 lookup 5000
   32766:  from all lookup main
   32767:  from all lookup default

   By default, RHEL contains rules for the tables local, main, and default.

2. Display the routes in table 5000:

   # ip route list table 5000
   default via 192.0.2.2 dev enp1s0
   10.0.0.0/24 via 192.0.2.1 dev enp1s0

3. Display the interfaces and firewall zones:

   # firewall-cmd --get-active-zones
   external
     interfaces: enp1s0 enp7s0
   internal
     interfaces: enp8s0 enp9s0

4. Verify that the external zone has masquerading enabled:

   # firewall-cmd --info-zone=external
   external (active)
     target: default
     icmp-block-inversion: no
     interfaces: enp1s0 enp7s0
     sources:
     services: ssh
     ports:
     protocols:
     masquerade: yes
     ...

Procedure

1. Display the network interfaces:

   # nmcli device status
   DEVICE   TYPE      STATE         CONNECTION
   enp1s0   ethernet  disconnected  enp1s0
   bridge0  bridge    connected     bridge0
   bond0    bond      connected     bond0
   ...

2. Create the VLAN interface. For example, to create a VLAN interface named vlan10 that uses enp1s0 as its parent interface and that tags packets with VLAN ID 10, enter:

   # nmcli connection add type vlan con-name vlan10 ifname vlan10 vlan.parent enp1s0 vlan.id 10

   Note that the VLAN must be within the range from 0 to 4094.

3. By default, the VLAN connection inherits the maximum transmission unit (MTU) from the parent interface. Optionally, set a different MTU value:

   # nmcli connection modify vlan10 802-3-ethernet.mtu 2000

4. Configure the IP settings of the VLAN device. Skip this step if you want to use this VLAN device as a slave of other devices.

   1. Configure the IPv4 settings. For example, to set a static IPv4 address, network mask, default gateway, and DNS server to the vlan10 connection, enter:

      # nmcli connection modify vlan10 ipv4.addresses '192.0.2.1/24'
      # nmcli connection modify vlan10 ipv4.gateway '192.0.2.254'
      # nmcli connection modify vlan10 ipv4.dns '192.0.2.253'
      # nmcli connection modify vlan10 ipv4.method manual

   2. Configure the IPv6 settings. For example, to set a static IPv6 address, network mask, default gateway, and DNS server to the vlan10 connection, enter:

      # nmcli connection modify vlan10 ipv6.addresses '2001:db8:1::1/32'
      # nmcli connection modify vlan10 ipv6.gateway '2001:db8:1::fffe'
      # nmcli connection modify vlan10 ipv6.dns '2001:db8:1::fffd'
      # nmcli connection modify vlan10 ipv6.method manual

5. Activate the connection:

   # nmcli connection up vlan10

Verification steps

1. Verify the settings:

   # ip -d addr show vlan10
   4: vlan10@enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
       link/ether 52:54:00:d5:e0:fb brd ff:ff:ff:ff:ff:ff promiscuity 0
       vlan protocol 802.1Q id 10 <REORDER_HDR> numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
       inet 192.0.2.1/24 brd 192.0.2.255 scope global noprefixroute vlan10
          valid_lft forever preferred_lft forever
       inet6 2001:db8:1::1/32 scope global noprefixroute
          valid_lft forever preferred_lft forever
       inet6 fe80::8dd7:9030:6f8e:89e6/64 scope link noprefixroute
          valid_lft forever preferred_lft forever

Procedure

1. Open a terminal, and enter nm-connection-editor:

   $ nm-connection-editor

2. Click the + button to add a new connection.
3. Select the VLAN connection type, and click Create.

4. On the VLAN tab:

   1. Select the parent interface.
   2. Select the VLAN id. Note that the VLAN must be within the range from 0 to 4094.
   3. By default, the VLAN connection inherits the maximum transmission unit (MTU) from the parent interface. Optionally, set a different MTU value.

   4. Optionally, set the name of the VLAN interface and further VLAN-specific options.

      

5. Configure the IP settings of the VLAN device. Skip this step if you want to use this VLAN device as a slave of other devices.

   1. On the IPv4 Settings tab, configure the IPv4 settings. For example, set a static IPv4 address, network mask, default gateway, and DNS server:
   2. On the IPv6 Settings tab, configure the IPv6 settings. For example, set a static IPv6 address, network mask, default gateway, and DNS server:
6. Click Save to save the VLAN connection.
7. Close nm-connection-editor.

Verification steps

1. Verify the settings:

   # ip -d addr show vlan10
   4: vlan10@enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
       link/ether 52:54:00:d5:e0:fb brd ff:ff:ff:ff:ff:ff promiscuity 0
       vlan protocol 802.1Q id 10 <REORDER_HDR> numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
       inet 192.0.2.1/24 brd 192.0.2.255 scope global noprefixroute vlan10
          valid_lft forever preferred_lft forever
       inet6 2001:db8:1::1/32 scope global noprefixroute
          valid_lft forever preferred_lft forever
       inet6 fe80::8dd7:9030:6f8e:89e6/64 scope link noprefixroute
          valid_lft forever preferred_lft forever

Procedure

1. Create a bridge interface:

   # nmcli connection add type bridge con-name bridge0 ifname bridge0

   This command creates a bridge named bridge0, enter:

2. Display the network interfaces, and note the names of the interfaces you want to add to the bridge:

   # nmcli device status
   DEVICE  TYPE      STATE         CONNECTION
   enp7s0  ethernet  disconnected  --
   enp8s0  ethernet  disconnected  --
   bond0   bond      connected     bond0
   bond1   bond      connected     bond1
   ...

   In this example:

   • enp7s0 and enp8s0 are not configured. To use these devices as slaves, add connection profiles in the next step.
   • bond0 and bond1 have existing connection profiles. To use these devices as slaves, modify their profiles in the next step.

3. Assign the interfaces to the bridge.

   1. If the interfaces you want to assign to the bridge are not configured, create new connection profiles for them:

      # nmcli connection add type ethernet slave-type bridge con-name bridge0-port1 ifname enp7s0 master bridge0
      # nmcli connection add type ethernet slave-type bridge con-name bridge0-port2 ifname enp8s0 master bridge0

      These commands create profiles for enp7s0 and enp8s0, and add them to the bridge0 connection.

   2. To assign an existing connection profile to the bridge, set the master parameter of these connections to bridge0:

      # nmcli connection modify bond0 master bridge0
      # nmcli connection modify bond1 master bridge0

      These commands assign the existing connection profiles named bond0 and bond1 to the bridge0 connection.

4. Configure the IP settings of the bridge. Skip this step if you want to use this bridge as a slave of other devices.

   1. Configure the IPv4 settings. For example, to set a static IPv4 address, network mask, default gateway, DNS server, and DNS search domain of the bridge0 connection, enter:

      # nmcli connection modify bridge0 ipv4.addresses '192.0.2.1/24'
      # nmcli connection modify bridge0 ipv4.gateway '192.0.2.254'
      # nmcli connection modify bridge0 ipv4.dns '192.0.2.253'
      # nmcli connection modify bridge0 ipv4.dns-search 'example.com'
      # nmcli connection modify bridge0 ipv4.method manual

   2. Configure the IPv6 settings. For example, to set a static IPv6 address, network mask, default gateway, DNS server, and DNS search domain of the bridge0 connection, enter:

      # nmcli connection modify bridge0 ipv6.addresses '2001:db8:1::1/64'
      # nmcli connection modify bridge0 ipv6.gateway '2001:db8:1::fffe'
      # nmcli connection modify bridge0 ipv6.dns '2001:db8:1::fffd'
      # nmcli connection modify bridge0 ipv6.dns-search 'example.com'
      # nmcli connection modify bridge0 ipv6.method manual

5. Optional: Configure further properties of the bridge. For example, to set the Spanning Tree Protocol (STP) priority of bridge0 to 16384, enter:

   # nmcli connection modify bridge0 bridge.priority '16384'

   By default, STP is enabled.

6. Activate the connection:

   # nmcli connection up bridge0

7. Verify that the slave devices are connected, and the CONNECTION column displays the slave’s connection name:

   # nmcli device
   DEVICE   TYPE      STATE      CONNECTION
   ...
   enp7s0   ethernet  connected  bridge0-port1
   enp8s0   ethernet  connected  bridge0-port2

   Red Hat Enterprise Linux activates master and slave devices when the system boots. By activating any slave connection, the master is also activated. However, in this case, only one slave connection is activated. By default, activating the master does not automatically activate the slaves. However, you can enable this behavior by setting:

   1. Enable the connection.autoconnect-slaves parameter of the bridge connection:

      # nmcli connection modify bridge0 connection.autoconnect-slaves 1

   2. Reactivate the bridge:

      # nmcli connection up bridge0

Procedure

1. Open a terminal, and enter nm-connection-editor:

   $ nm-connection-editor

2. Click the + button to add a new connection.
3. Select the Bridge connection type, and click Create.

4. In the Bridge tab:

   1. Optional: Set the name of the bridge interface in the Interface name field.

   2. Click the Add button to create a new connection profile for a network interface and adding the profile as a slave to the bridge.

      1. Select the connection type of the interface. For example, select Ethernet for a wired connection.
      2. Optionally, set a connection name for the slave device.
      3. If you create a connection profile for an Ethernet device, open the Ethernet tab, and select in the Device field the network interface you want to add as a slave to the bridge. If you selected a different device type, configure it accordingly.
      4. Click Save.

   3. Repeat the previous step for each interface you want to add to the bridge.

      

5. Optional: Configure further bridge settings, such as Spanning Tree Protocol (STP) options.

6. Configure the IP settings of the bridge. Skip this step if you want to use this bridge as a slave of other devices.

   1. In the IPv4 Settings tab, configure the IPv4 settings. For example, set a static IPv4 address, network mask, default gateway, DNS server, and DNS search domain:

      

   2. In the IPv6 Settings tab, configure the IPv6 settings. For example, set a static IPv6 address, network mask, default gateway, DNS server, and DNS search domain:

      

7. Save the bridge connection.
8. Close nm-connection-editor.

Procedure

1. Install the teamd and NetworkManager-team packages:

   # yum install teamd NetworkManager-team

Procedure

1. Create a team interface:

   # nmcli connection add type team con-name team0 ifname team0 team.runner activebackup

   This command creates a network team named team0 that uses the activebackup runner.

2. Optionally, set a link watcher. For example, to set the ethtool link watcher in the team0 connection profile:

   # nmcli connection modify team0 team.link-watchers "name=ethtool"

   Link watchers support different parameters. To set parameters for a link watcher, specify them space-separated in the name property. Note that the name property must be surrounded by quotes. For example, to use the ethtool link watcher and set its delay-up parameter to 2500 milliseconds (2.5 seconds):

   # nmcli connection modify team0 team.link-watchers "name=ethtool delay-up=2500"

   To set multiple link watchers and each of them with specific parameters, the link watchers must be separated by a comma. The following example sets the ethtool link watcher with the delay-up parameter and the arp_ping link watcher with the source-host and target-host parameter:

   # nmcli connection modify team0 team.link-watchers "name=ethtool delay-up=2, name=arp_ping source-host=192.0.2.1 target-host=192.0.2.2"

3. Display the network interfaces, and note the names of the interfaces you want to add to the team:

   # nmcli device status
   DEVICE  TYPE      STATE         CONNECTION
   enp7s0  ethernet  disconnected  --
   enp8s0  ethernet  disconnected  --
   bond0   bond      connected  bond0
   bond1   bond      connected  bond1
   ...

   In this example:

   • enp7s0 and enp8s0 are not configured. To use these devices as slaves, add connection profiles in the next step. Note that you can only use Ethernet interfaces in a team that are not assigned to any connection.
   • bond0 and bond1 have existing connection profiles. To use these devices as slaves, modify their profiles in the next step.

4. Assign the port interfaces to the team:

   1. If the interfaces you want to assign to the team are not configured, create new connection profiles for them:

      # nmcli connection add type ethernet slave-type team con-name team0-port1 ifname enp7s0 master team0
      # nmcli connection add type ethernet slave-type team con-name team0-port2 ifname enp8s0 master team0

      . These commands create profiles for enp7s0 and enp8s0, and add them to the team0 connection.

   2. To assign an existing connection profile to the team, set the master parameter of these connections to team0:

      # nmcli connection modify bond0 master team0
      # nmcli connection modify bond1 master team0

      These commands assign the existing connection profiles named bond0 and bond1 to the team0 connection.

5. Configure the IP settings of the team. Skip this step if you want to use this team as a slave of other devices.

   1. Configure the IPv4 settings. For example, to set a static IPv4 address, network mask, default gateway, DNS server, and DNS search domain the team0 connection, enter:

      # nmcli connection modify team0 ipv4.addresses '192.0.2.1/24'
      # nmcli connection modify team0 ipv4.gateway '192.0.2.254'
      # nmcli connection modify team0 ipv4.dns '192.0.2.253'
      # nmcli connection modify team0 ipv4.dns-search 'example.com'
      # nmcli connection modify team0 ipv4.method manual

   2. Configure the IPv6 settings. For example, to set a static IPv6 address, network mask, default gateway, DNS server, and DNS search domain of the team0 connection, enter:

      # nmcli connection modify team0 ipv6.addresses '2001:db8:1::1/64'
      # nmcli connection modify team0 ipv6.gateway '2001:db8:1::fffe'
      # nmcli connection modify team0 ipv6.dns '2001:db8:1::fffd'
      # nmcli connection modify team0 ipv6.dns-search 'example.com'
      # nmcli connection modify team0 ipv6.method manual

6. Activate the connection:

   # nmcli connection up team0

Procedure

1. Open a terminal, and enter nm-connection-editor:

   $ nm-connection-editor

2. Click the + button to add a new connection.
3. Select the Team connection type, and click Create.

4. In the Team tab:

   1. Optional: Set the name of the team interface in the Interface name field.

   2. Click the Add button to add a new connection profile for a network interface and adding the profile as a slave to the team.

      1. Select the connection type of the interface. For example, select Ethernet for a wired connection.
      2. Optional: Set a connection name for the slave device.
      3. If you create a connection profile for an Ethernet device, open the Ethernet tab, and select in the Device field the network interface you want to add as a slave to the team. If you selected a different device type, configure it accordingly. Note that you can only use Ethernet interfaces in a team that are not assigned to any connection.
      4. Click Save.

   3. Repeat the previous step for each interface you want to add to the team.

      

   4. Click the Advanced button to set advanced options to the team connection.

      1. In the Runner tab, select the runner.
      2. In the Link Watcher tab, set the link watcher and its optional settings.
      3. Click OK.

5. Configure the IP settings of the team. Skip this step if you want to use this team as a slave of other devices.

   1. In the IPv4 Settings tab, configure the IPv4 settings. For example, set a static IPv4 address, network mask, default gateway, DNS server, and DNS search domain:
   2. In the IPv6 Settings tab, configure the IPv6 settings. For example, set a static IPv6 address, network mask, default gateway, DNS server, and DNS search domain:
6. Save the team connection.
7. Close nm-connection-editor.

Procedure

1. Create a bond interface:

   # nmcli connection add type bond con-name bond0 ifname bond0 bond.options "mode=active-backup"

   This command creates a bond named bond0 that uses the active-backup mode.

   To additionally set a Media Independent Interface (MII) monitoring interval, add the miimon=interval option to the bond.options property. For example, to use the same command but, additionally, set the MII monitoring interval to 1000 milliseconds (1 second), enter:

   # nmcli connection add type bond con-name bond0 ifname bond0 bond.options "mode=active-backup,miimon=1000"

2. Display the network interfaces, and note names of interfaces you plan to add to the bond:

   # nmcli device status
   DEVICE   TYPE      STATE         CONNECTION
   enp7s0   ethernet  disconnected  --
   enp8s0   ethernet  disconnected  --
   bridge0  bridge    connected     bridge0
   bridge1  bridge    connected     bridge1
   ...

   In this example:

   • enp7s0 and enp8s0 are not configured. To use these devices as slaves, add connection profiles in the next step.
   • bridge0 and bridge1 have existing connection profiles. To use these devices as slaves, modify their profiles in the next step.

3. Assign interfaces to the bond:

   1. If the interfaces you want to assign to the bond are not configured, create new connection profiles for them:

      # nmcli connection add type ethernet slave-type bond con-name bond0-port1 ifname enp7s0 master bond0
      # nmcli connection add type ethernet slave-type bond con-name bond0-port2 ifname enp8s0 master bond0

      These commands create profiles for enp7s0 and enp8s0, and add them to the bond0 connection.

   2. To assign an existing connection profile to the bond, set the master parameter of these connections to bond0:

      # nmcli connection modify bridge0 master bond0
      # nmcli connection modify bridge1 master bond0

      These commands assign the existing connection profiles named bridge0 and bridge1 to the bond0 connection.

4. Configure the IP settings of the bond. Skip this step if you want to use this bond as a slave of other devices.

   1. Configure the IPv4 settings. For example, to set a static IPv4 address, network mask, default gateway, DNS server, and DNS search domain to the bond0 connection, enter:

      # nmcli connection modify bond0 ipv4.addresses '192.0.2.1/24'
      # nmcli connection modify bond0 ipv4.gateway '192.0.2.254'
      # nmcli connection modify bond0 ipv4.dns '192.0.2.253'
      # nmcli connection modify bond0 ipv4.dns-search 'example.com'
      # nmcli connection modify bond0 ipv4.method manual

   2. Configure the IPv6 settings. For example, to set a static IPv6 address, network mask, default gateway, DNS server, and DNS search domain to the bond0 connection, enter:

      # nmcli connection modify bond0 ipv6.addresses '2001:db8:1::1/64
      # nmcli connection modify bond0 ipv6.gateway '2001:db8:1::fffe'
      # nmcli connection modify bond0 ipv6.dns '2001:db8:1::fffd'
      # nmcli connection modify bond0 ipv6.dns-search 'example.com'
      # nmcli connection modify bond0 ipv6.method manual

5. Activate the connection:

   # nmcli connection up bond0

6. Verify that the slave devices are connected, and the CONNECTION column displays the slave’s connection name:

   # nmcli device
   DEVICE   TYPE      STATE      CONNECTION
   ...
   enp7s0   ethernet  connected  bond0-port1
   enp8s0   ethernet  connected  bond0-port2

   Red Hat Enterprise Linux activates master and slave devices when the system boots. By activating any slave connection, the master is also activated. However, in this case, only one slave connection is activated. By default, activating the master does not automatically activate the slaves. However, you can enable this behavior by setting:

   1. Enable the connection.autoconnect-slaves parameter of the bond’s connection:

      # nmcli connection modify bond0 connection.autoconnect-slaves 1

   2. Reactivate the bridge:

      # nmcli connection up bond0

Verification steps

1. Display the status of the bond:

   # cat /proc/net/bonding/bond0
   Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)
   
   Bonding Mode: fault-tolerance (active-backup)
   Primary Slave: None
   Currently Active Slave: enp7s0
   MII Status: up
   MII Polling Interval (ms): 100
   Up Delay (ms): 0
   Down Delay (ms): 0
   
   Slave Interface: enp7s0
   MII Status: up
   Speed: Unknown
   Duplex: Unknown
   Link Failure Count: 0
   Permanent HW addr: 52:54:00:d5:e0:fb
   Slave queue ID: 0
   
   Slave Interface: enp8s0
   MII Status: up
   Speed: Unknown
   Duplex: Unknown
   Link Failure Count: 0
   Permanent HW addr: 52:54:00:b2:e2:63
   Slave queue ID: 0

   In this example, both ports are up.

2. To verify that bonding failover works:

   1. Temporarily remove the network cable from the host. Note that there is no method to properly test link failure events using the command line.

   2. Display the status of the bond:

      # cat /proc/net/bonding/bond0

Procedure

1. Open a terminal, and enter nm-connection-editor:

   $ nm-connection-editor

2. Click the + button to add a new connection.
3. Select the Bond connection type, and click Create.

4. In the Bond tab:

   1. Optional: Set the name of the bond interface in the Interface name field.

   2. Click the Add button to add a network interface as a slave to the bond.

      1. Select the connection type of the interface. For example, select Ethernet for a wired connection.
      2. Optional: Set a connection name for the slave device.
      3. If you create a connection profile for an Ethernet device, open the Ethernet tab, and select in the Device field the network interface you want to add as a slave to the bond. If you selected a different device type, configure it accordingly. Note that you can only use Ethernet interfaces in a bond that are not configured.
      4. Click Save.

   3. Repeat the previous step for each interface you want to add to the bond:

      

   4. Optional: Set other options, such as the Media Independent Interface (MII) monitoring interval.

5. Configure the IP settings of the bond. Skip this step if you want to use this bond as a slave of other devices.

   1. In the IPv4 Settings tab, configure the IPv4 settings. For example, set a static IPv4 address, network mask, default gateway, DNS server, and DNS search domain:

      

   2. In the IPv6 Settings tab, configure the IPv6 settings. For example, set a static IPv6 address, network mask, default gateway, DNS server, and DNS search domain:

      

6. Click Save to save the bond connection.
7. Close nm-connection-editor.

Procedure

1. Create a bond interface in active-backup mode:

   # nmcli connection add type bond con-name bond0 ifname bond0 bond.options "mode=active-backup"

   This command names both the interface and connection profile bond0.

2. Configure the IPv4 settings of the bond:

   • If a DHCP server in your network assigns IPv4 addresses to hosts, no action is required.

   • If your local network requires static IPv4 addresses, set the address, network mask, default gateway, DNS server, and DNS search domain to the bond0 connection:

     # nmcli connection modify bond0 ipv4.addresses '192.0.2.1/24'
     # nmcli connection modify bond0 ipv4.gateway '192.0.2.254'
     # nmcli connection modify bond0 ipv4.dns '192.0.2.253'
     # nmcli connection modify bond0 ipv4.dns-search 'example.com'
     # nmcli connection modify bond0 ipv4.method manual

3. Configure the IPv6 settings of the bond:

   • If your router or a DHCP server in your network assigns IPv6 addresses to hosts, no action is required.

   • If your local network requires static IPv6 addresses, set the address, network mask, default gateway, DNS server, and DNS search domain to the bond0 connection:

     # nmcli connection modify bond0 ipv6.addresses '2001:db8:1::1/64'
     # nmcli connection modify bond0 ipv6.gateway '2001:db8:1::fffe'
     # nmcli connection modify bond0 ipv6.dns '2001:db8:1::fffd'
     # nmcli connection modify bond0 ipv6.dns-search 'example.com'
     # nmcli connection modify bond0 ipv6.method manual

4. Display the connection profiles:

   # nmcli connection show
   NAME             UUID                                  TYPE      DEVICE
   Docking_station  256dd073-fecc-339d-91ae-9834a00407f9  ethernet  enp11s0u1
   Wi-Fi            1f1531c7-8737-4c60-91af-2d21164417e8  wifi      wlp61s0
   ...

   You require the names of the connection profiles and the Ethernet device name in the next steps.

5. Assign the connection profile of the Ethernet connection to the bond:

   # nmcli connection modify Docking_station master bond0

6. Assign the connection profile of the Wi-Fi connection to the bond:

   # nmcli connection modify Wi-Fi master bond0

7. If your Wi-Fi network uses MAC filtering to allow only MAC addresses on a white list to access the network, configure that NetworkManager dynamically assigns the MAC address of the active slave device to the bond:

   # nmcli connection modify bond0 +bond.options fail_over_mac=1

   With this setting, you must set only the MAC address of the Wi-Fi device to the white list instead of the MAC address of both the Ethernet and Wi-Fi device.

8. Set the device associated with the Ethernet connection as primary device of the bond:

   # nmcli con modify bond0 +bond.options "primary=enp11s0u1"

   With this setting, the bond always uses the Ethernet connection if it is available.

9. Configure that NetworkManager automatically activates slave devices when the bond0 device is activated:

   # nmcli connection modify bond0 connection.autoconnect-slaves 1

10. Activate the bond0 connection:

    # nmcli connection up bond0

Procedure

1. Install the fcoe-utils package:

   # yum install fcoe-utils

2. Copy the /etc/fcoe/cfg-ethx template file to /etc/fcoe/cfg-interface_name. For example, if you want to configure the enp1s0 interface to use FCoE, enter:

   # cp /etc/fcoe/cfg-ethx /etc/fcoe/cfg-enp1s0

3. Enable and start the fcoe service:

   # systemctl enable --now fcoe

4. Discover the FCoE VLAN ID, start the initiator, and create a network device for the discovered VLAN:

   # fipvlan -s -c enp1s0
   Created VLAN device enp1s0.200
   Starting FCoE on interface enp1s0.200
   Fibre Channel Forwarders Discovered
   interface       | VLAN | FCF MAC
   ------------------------------------------
   enp1s0          | 200  | 00:53:00:a7:e7:1b

5. Optional: To display details about the discovered targets, the LUNs, and the devices associated with the LUNs, enter:

   # fcoeadm -t
   Interface:        enp1s0.200
   Roles:            FCP Target
   Node Name:        0x500a0980824acd15
   Port Name:        0x500a0982824acd15
   Target ID:        0
   MaxFrameSize:     2048 bytes
   OS Device Name:   rport-11:0-1
   FC-ID (Port ID):  0xba00a0
   State:            Online
   
   LUN ID  Device Name   Capacity   Block Size  Description
   ------  -----------  ----------  ----------  ---------------------
        0  sdb           28.38 GiB      512     NETAPP LUN (rev 820a)
        ...

   This example shows that LUN 0 from the SAN has been attached to the host as the /dev/sdb device.

Procedure

1. Press the Super key, type Settings, and press Enter to open the control-center application.
2. Select the Network entry on the left.
3. Click the + icon.
4. Select VPN.

5. Select the Identity menu entry to see the basic configuration options:

   General

   Gateway — The name or IP address of the remote VPN gateway.

   Authentication

   Type

   • IKEv2 (Certificate)- client is authenticated by certificate. It is more secure (default).

   • IKEv1 (XAUTH) - client is authenticated by user name and password, or a pre-shared key (PSK).

     The following configuration settings are available under the Advanced section:

     Figure 22.1. Advanced options of a VPN connection

     
     Warning

     When configuring an IPsec-based VPN connection using the gnome-control-center application, the Advanced dialog displays the configuration, but it does not allow any changes. As a consequence, users cannot change any advanced IPsec options. Use the nm-connection-editor or nmcli tools instead to perform configuration of the advanced properties.

     Identification

   • Domain — If required, enter the Domain Name.

     Security

   • Phase1 Algorithms — corresponds to the ike Libreswan parameter — enter the algorithms to be used to authenticate and set up an encrypted channel.

   • Phase2 Algorithms — corresponds to the esp Libreswan parameter — enter the algorithms to be used for the IPsec negotiations.

     Check the Disable PFS field to turn off Perfect Forward Secrecy (PFS) to ensure compatibility with old servers that do not support PFS.

   • Phase1 Lifetime — corresponds to the ikelifetime Libreswan parameter — how long the key used to encrypt the traffic will be valid.

   • Phase2 Lifetime — corresponds to the salifetime Libreswan parameter — how long a particular instance of a connection should last before expiring.

     Note that the encryption key should be changed from time to time for security reasons.

   • Remote network — corresponds to the rightsubnet Libreswan parameter — the destination private remote network that should be reached through the VPN.

     Check the narrowing field to enable narrowing. Note that it is only effective in IKEv2 negotiation.

   • Enable fragmentation — corresponds to the fragmentation Libreswan parameter — whether or not to allow IKE fragmentation. Valid values are yes (default) or no.
   • Enable Mobike — corresponds to the mobike Libreswan parameter — whether to allow Mobility and Multihoming Protocol (MOBIKE, RFC 4555) to enable a connection to migrate its endpoint without needing to restart the connection from scratch. This is used on mobile devices that switch between wired, wireless, or mobile data connections. The values are no (default) or yes.

6. Select the IPv4 menu entry:

   IPv4 Method

   • Automatic (DHCP) — Choose this option if the network you are connecting to uses Router Advertisements (RA) or a DHCP server to assign dynamic IP addresses.
   • Link-Local Only — Choose this option if the network you are connecting to does not have a DHCP server and you do not want to assign IP addresses manually. Random addresses will be assigned as per RFC 3927 with prefix 169.254/16.
   • Manual — Choose this option if you want to assign IP addresses manually.

   • Disable — IPv4 is disabled for this connection.

     DNS

     In the DNS section, when Automatic is ON, switch it to OFF to enter the IP address of a DNS server you want to use separating the IPs by comma.

     Routes

     Note that in the Routes section, when Automatic is ON, routes from DHCP are used, but you can also add additional static routes. When OFF, only static routes are used.

   • Address — Enter the IP address of a remote network or host.
   • Netmask — The netmask or prefix length of the IP address entered above.
   • Gateway — The IP address of the gateway leading to the remote network or host entered above.

   • Metric — A network cost, a preference value to give to this route. Lower values will be preferred over higher values.

     Use this connection only for resources on its network

     Select this check box to prevent the connection from becoming the default route. Selecting this option means that only traffic specifically destined for routes learned automatically over the connection or entered here manually is routed over the connection.

7. To configure IPv6 settings in a VPN connection, select the IPv6 menu entry:

   IPv6 Method

   • Automatic — Choose this option to use IPv6 Stateless Address AutoConfiguration (SLAAC) to create an automatic, stateless configuration based on the hardware address and Router Advertisements (RA).
   • Automatic, DHCP only — Choose this option to not use RA, but request information from DHCPv6 directly to create a stateful configuration.
   • Link-Local Only — Choose this option if the network you are connecting to does not have a DHCP server and you do not want to assign IP addresses manually. Random addresses will be assigned as per RFC 4862 with prefix FE80::0.
   • Manual — Choose this option if you want to assign IP addresses manually.

   • Disable — IPv6 is disabled for this connection.

     Note that DNS, Routes, Use this connection only for resources on its network are common to IPv4 settings.

8. Once you have finished editing the VPN connection, click the Add button to customize the configuration or the Apply button to save it for the existing one.
9. Switch the profile to ON to active the VPN connection.

Procedure

1. Open a terminal, and enter:

   $ nm-connection-editor

2. Click the + button to add a new connection.
3. Select the IPsec based VPN connection type, and click Create.

4. On the VPN tab:

   1. Enter the host name or IP address of the VPN gateway into the Gateway field, and select an authentication type. Based on the authentication type, you must enter different additional information:

      • IKEv2 (Certifiate) authenticates the client by using a certificate, which is more secure. This setting requires the nickname of the certificate in the IPsec NSS database

      • IKEv1 (XAUTH) authenticates the user by using a user name and password (pre-shared key). This setting requires that you enter the following values:

        • User name
        • Password
        • Group name
        • Secret

   2. If the remote server specifies a local identifier for the IKE exchange, enter the exact string in the Remote ID field. In the remote server runs Libreswan, this value is set in the server’s leftid parameter.

      

   3. Optionally, configure additional settings by clicking the Advanced button. You can configure the following settings:

      • Identification

        • Domain — If required, enter the domain name.

      • Security

        • Phase1 Algorithms corresponds to the ike Libreswan parameter. Enter the algorithms to be used to authenticate and set up an encrypted channel.

        • Phase2 Algorithms corresponds to the esp Libreswan parameter. Enter the algorithms to be used for the IPsec negotiations.

          Check the Disable PFS field to turn off Perfect Forward Secrecy (PFS) to ensure compatibility with old servers that do not support PFS.

        • Phase1 Lifetime corresponds to the ikelifetime Libreswan parameter. This parameter defines how long the key used to encrypt the traffic is valid.
        • Phase2 Lifetime corresponds to the salifetime Libreswan parameter. This parameter defines how long a security association is valid.

      • Connectivity

        • Remote network corresponds to the rightsubnet Libreswan parameter and defines the destination private remote network that should be reached through the VPN.

          Check the narrowing field to enable narrowing. Note that it is only effective in the IKEv2 negotiation.

        • Enable fragmentation corresponds to the fragmentation Libreswan parameter and defines whether or not to allow IKE fragmentation. Valid values are yes (default) or no.
        • Enable Mobike corresponds to the mobike Libreswan parameter. The parameter defines whether to allow Mobility and Multihoming Protocol (MOBIKE) (RFC 4555) to enable a connection to migrate its endpoint without needing to restart the connection from scratch. This is used on mobile devices that switch between wired, wireless or mobile data connections. The values are no (default) or yes.

5. On the IPv4 Settings tab, select the IP assignment method and, optionally, set additional static addresses, DNS servers, search domains, and routes.

   

6. Save the connection.
7. Close nm-connection-editor.

Procedure

1. To create a dummy interface named dummy0 with static IPv4 and IPv6 addresses, enter:

   # nmcli connection add type dummy ifname dummy0 ipv4.method manual ipv4.addresses 192.0.2.1/24 ipv6.method manual ipv6.addresses 2001:db8:2::1/64

2. Optional:To view the dummy interface, enter:

   # nmcli connection show
   NAME            UUID                                  TYPE      DEVICE
   enp1s0          db1060e9-c164-476f-b2b5-caec62dc1b05  ethernet    ens3
   dummy-dummy0    aaf6eb56-73e5-4746-9037-eed42caa8a65  dummy    dummy0

Procedure

1. On the RHEL router in network A:

   1. Create an IPIP tunnel interface named tun0:

      # nmcli connection add type ip-tunnel ip-tunnel.mode ipip con-name tun0 ifname tun0 remote 198.51.100.5 local 203.0.113.10

      The remote and local parameters set the public IP addresses of the remote and the local routers.

   2. Set the IPv4 address to the tun0 device:

      # nmcli connection modify tun0 ipv4.addresses '10.0.1.1/30'

      Note that a /30 subnet with two usable IP addresses is sufficient for the tunnel.

   3. Configure the tun0 connection to use a manual IPv4 configuration:

      # nmcli connection modify tun0 ipv4.method manual

   4. Add a static route that routes traffic to the 172.16.0.0/24 network to the tunnel IP on router B:

      # nmcli connection modify tun0 +ipv4.routes "172.16.0.0/24 10.0.1.2"

   5. Enable the tun0 connection.

      # nmcli connection up tun0

   6. Enable packet forwarding:

      # echo "net.ipv4.ip_forward=1" > /etc/sysctl.d/95-IPv4-forwarding.conf
      # sysctl -p /etc/sysctl.d/95-IPv4-forwarding.conf

2. On the RHEL router in network B:

   1. Create an IPIP tunnel interface named tun0:

      # nmcli connection add type ip-tunnel ip-tunnel.mode ipip con-name tun0 ifname tun0 remote 203.0.113.10 local 198.51.100.5

      The remote and local parameters set the public IP addresses of the remote and local routers.

   2. Set the IPv4 address to the tun0 device:

      # nmcli connection modify tun0 ipv4.addresses '10.0.1.2/30'

   3. Configure the tun0 connection to use a manual IPv4 configuration:

      # nmcli connection modify tun0 ipv4.method manual

   4. Add a static route that routes traffic to the 192.0.2.0/24 network to the tunnel IP on router A:

      # nmcli connection modify tun0 +ipv4.routes "192.0.2.0/24 10.0.1.1"

   5. Enable the tun0 connection.

      # nmcli connection up tun0

   6. Enable packet forwarding:

      # echo "net.ipv4.ip_forward=1" > /etc/sysctl.d/95-IPv4-forwarding.conf
      # sysctl -p /etc/sysctl.d/95-IPv4-forwarding.conf

Verification steps

1. From each RHEL router, ping the IP address of the internal interface of the other router:

   1. On Router A, ping 172.16.0.1:

      # ping 172.16.0.1

   2. On Router B, ping 192.0.2.1:

      # ping 192.0.2.1

Procedure

1. On the RHEL router in network A:

   1. Create a GRE tunnel interface named gre1:

      # nmcli connection add type ip-tunnel ip-tunnel.mode gre con-name gre1 ifname gre1 remote 198.51.100.5 local 203.0.113.10

      The remote and local parameters set the public IP addresses of the remote and the local routers.

   2. Set the IPv4 address to the gre1 device:

      # nmcli connection modify gre1 ipv4.addresses '10.0.1.1/30'

      Note that a /30 subnet with two usable IP addresses is sufficient for the tunnel.

   3. Configure the gre1 connection to use a manual IPv4 configuration:

      # nmcli connection modify gre1 ipv4.method manual

   4. Add a static route that routes traffic to the 172.16.0.0/24 network to the tunnel IP on router B:

      # nmcli connection modify tun0 +ipv4.routes "172.16.0.0/24 10.0.1.2"

   5. Enable the gre1 connection.

      # nmcli connection up gre1

   6. Enable packet forwarding:

      # echo "net.ipv4.ip_forward=1" > /etc/sysctl.d/95-IPv4-forwarding.conf
      # sysctl -p /etc/sysctl.d/95-IPv4-forwarding.conf

2. On the RHEL router in network B:

   1. Create a GRE tunnel interface named gre1:

      # nmcli connection add type ip-tunnel ip-tunnel.mode ipip con-name gre1 ifname gre1 remote 203.0.113.10 local 198.51.100.5

      The remote and local parameters sets the public IP addresses of the remote and the local routers.

   2. Set the IPv4 address to the gre1 device:

      # nmcli connection modify gre1 ipv4.addresses '10.0.1.2/30'

   3. Configure the gre1 connection to use a manual IPv4 configuration:

      # nmcli connection modify gre1 ipv4.method manual

   4. Add a static route that routes traffic to the 192.0.2.0/24 network to the tunnel IP on router A:

      # nmcli connection modify tun0 +ipv4.routes "192.0.2.0/24 10.0.1.1"

   5. Enable the gre1 connection.

      # nmcli connection up gre1

   6. Enable packet forwarding:

      # echo "net.ipv4.ip_forward=1" > /etc/sysctl.d/95-IPv4-forwarding.conf
      # sysctl -p /etc/sysctl.d/95-IPv4-forwarding.conf

Verification steps

1. From each RHEL router, ping the IP address of the internal interface of the other router:

   1. On Router A, ping 172.16.0.1:

      # ping 172.16.0.1

   2. On Router B, ping 192.0.2.1:

      # ping 192.0.2.1

Procedure

1. On the RHEL router in network A:

   1. Create a bridge interface named bridge0:

      # nmcli connection add type bridge con-name bridge0 ifname bridge0

   2. Configure the IP settings of the bridge:

      # nmcli connection modify bridge0 ipv4.addresses '192.0.2.1/24'
      # nmcli connection modify bridge0 ipv4.method manual

   3. Add a new connection profile for the interface that is connected to local network to the bridge:

      # nmcli connection add type ethernet slave-type bridge con-name bridge0-port1 ifname enp1s0 master bridge0

   4. Add a new connection profile for the GRETAP tunnel interface to the bridge:

      # nmcli connection add type ip-tunnel ip-tunnel.mode gretap slave-type bridge con-name bridge0-port2 ifname gretap1 remote 198.51.100.5 local 203.0.113.10 master bridge0

      The remote and local parameters set the public IP addresses of the remote and the local routers.

   5. Optional: Disable the Spanning Tree Protocol (STP) if you do not need it:

      # nmcli connection modify bridge0 bridge.stp no

      By default, STP is enabled and causes a delay before you can use the connection.

   6. Configure that activating the bridge0 connection automatically activates the slaves of the bridge:

      # nmcli connection modify bridge0 connection.autoconnect-slaves 1

   7. Active the bridge0 connection:

      # nmcli connection up bridge0

2. On the RHEL router in network B:

   1. Create a bridge interface named bridge0:

      # nmcli connection add type bridge con-name bridge0 ifname bridge0

   2. Configure the IP settings of the bridge:

      # nmcli connection modify bridge0 ipv4.addresses '192.0.2.2/24'
      # nmcli connection modify bridge0 ipv4.method manual

   3. Add a new connection profile for the interface that is connected to local network to the bridge:

      # nmcli connection add type ethernet slave-type bridge con-name bridge0-port1 ifname enp1s0 master bridge0

   4. Add a new connection profile for the GRETAP tunnel interface to the bridge:

      # nmcli connection add type ip-tunnel ip-tunnel.mode gretap slave-type bridge con-name bridge0-port2 ifname gretap1 remote 203.0.113.10 local 198.51.100.5 master bridge0

      The remote and local parameters set the public IP addresses of the remote and the local routers.

   5. Optional: Disable the Spanning Tree Protocol (STP) if you do not need it:

      # nmcli connection modify bridge0 bridge.stp no

   6. Configure that activating the bridge0 connection automatically activates the slaves of the bridge:

      # nmcli connection modify bridge0 connection.autoconnect-slaves 1

   7. Active the bridge0 connection:

      # nmcli connection up bridge0

Verification steps

1. On both routers, verify that the enp1s0 and gretap1 connections are connected and that the CONNECTION column displays the connection name of the slave:

   # nmcli device
   nmcli device
   DEVICE   TYPE      STATE      CONNECTION
   ...
   bridge0  bridge    connected  bridge0
   enp1s0   ethernet  connected  bridge0-port1
   gretap1  iptunnel  connected  bridge0-port2

2. From each RHEL router, ping the IP address of the internal interface of the other router:

   1. On Router A, ping 192.0.2.2:

      # ping 192.0.2.2

   2. On Router B, ping 192.0.2.1:

      # ping 192.0.2.1