Chapter 2. Configuring an Ethernet connection

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

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

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 quotation marks.

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

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

Procedure

1. If you do not know the network device name you want to use in the connection, display the available devices:

   # nmcli device status
   DEVICE     TYPE      STATE                   CONNECTION
   enp7s0     ethernet  unavailable             --
   ...

2. Start nmtui:

   # nmtui

3. Select Edit a connection, and press Enter.
4. Press the Add button.
5. Select Ethernet from the list of network types, and press Enter.
6. Optional: Enter a name for the NetworkManager profile to be created.
7. Enter the network device name into the Device field.

8. Configure the IPv4 and IPv6 address settings in the IPv4 configuration and IPv6 configuration areas:

   1. Press the Automatic button, and select Manual from the displayed list.
   2. Press the Show button next to the protocol you want to configure to display additional fields.

   3. Press the Add button next to Addresses, and enter the IP address and the subnet mask in Classless Inter-Domain Routing (CIDR) format.

      If you do not specify a subnet mask, NetworkManager sets a /32 subnet mask for IPv4 addresses and /64 for IPv6 addresses.

   4. Enter the address of the default gateway.
   5. Press the Add button next to DNS servers, and enter the DNS server address.
   6. Press the Add button next to Search domains, and enter the DNS search domain.

   Figure 2.1. Example of an Ethernet connection with static IP address settings

   
9. Press the OK button to create and automatically activate the new connection.
10. Press the Back button to return to the main menu.
11. Select Quit, and press Enter to close the nmtui application.

Verification

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

Procedure

1. Create a YAML file, for example ~/create-ethernet-profile.yml, with the following contents:

   ---
   interfaces:
   - name: enp7s0
     type: ethernet
     state: up
     ipv4:
       enabled: true
       address:
       - ip: 192.0.2.1
         prefix-length: 24
       dhcp: false
     ipv6:
       enabled: true
       address:
       - ip: 2001:db8:1::1
         prefix-length: 64
       autoconf: false
       dhcp: false
   routes:
     config:
     - destination: 0.0.0.0/0
       next-hop-address: 192.0.2.254
       next-hop-interface: enp7s0
     - destination: ::/0
       next-hop-address: 2001:db8:1::fffe
       next-hop-interface: enp7s0
   dns-resolver:
     config:
       search:
       - example.com
       server:
       - 192.0.2.200
       - 2001:db8:1::ffbb

2. Apply the settings to the system:

   # nmstatectl apply ~/create-ethernet-profile.yml

Verification

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  enp7s0

2. Display all settings of the connection profile:

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

3. Display the connection settings in YAML format:

   # nmstatectl show enp7s0

Procedure

1. Create a playbook file, for example ~/ethernet-static-IP.yml, with the following content:

   ---
   - name: Configure the network
     hosts: managed-node-01.example.com
     tasks:
     - name: Configure an Ethernet connection with static IP
       include_role:
         name: rhel-system-roles.network
   
       vars:
         network_connections:
           - name: enp7s0
             interface_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

2. Run the playbook:

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

Procedure

1. Create a playbook file, for example ~/ethernet-static-IP.yml, with the following content:

   ---
   - name: Configure the network
     hosts: managed-node-01.example.com
     tasks:
     - name: Configure an Ethernet connection with static IP
       include_role:
         name: rhel-system-roles.network
   
       vars:
         network_connections:
           - name: example
             match:
               path:
                 - pci-0000:00:0[1-3].0
                 - &!pci-0000:00:02.0
             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

   The match parameter in this example defines that Ansible applies the play to devices that match PCI ID 0000:00:0[1-3].0, but not 0000:00:02.0. For further details about special modifiers and wild cards you can use, see the match parameter description in the /usr/share/ansible/roles/rhel-system-roles.network/README.md file.

2. Run the playbook:

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

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

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

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

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

Procedure

1. If you do not know the network device name you want to use in the connection, display the available devices:

   # nmcli device status
   DEVICE     TYPE      STATE                   CONNECTION
   enp7s0     ethernet  unavailable             --
   ...

2. Start nmtui:

   # nmtui

3. Select Edit a connection, and press Enter.
4. Press the Add button.
5. Select Ethernet from the list of network types, and press Enter.
6. Optional: Enter a name for the NetworkManager profile to be created.
7. Enter the network device name into the Device field.

8. Press the OK button to create and automatically activate the new connection.

   
9. Press the Back button to return to the main menu.
10. Select Quit, and press Enter to close the nmtui application.

Verification

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

Procedure

1. Create a YAML file, for example ~/create-ethernet-profile.yml, with the following contents:

   ---
   interfaces:
   - name: enp7s0
     type: ethernet
     state: up
     ipv4:
       enabled: true
       auto-dns: true
       auto-gateway: true
       auto-routes: true
       dhcp: true
     ipv6:
       enabled: true
       auto-dns: true
       auto-gateway: true
       auto-routes: true
       autoconf: true
       dhcp: true

2. Apply the settings to the system:

   # nmstatectl apply ~/create-ethernet-profile.yml

Verification

1. Display the status of the devices and connections:

   # nmcli device status
   DEVICE      TYPE      STATE      CONNECTION
   enp7s0      ethernet  connected  enp7s0

2. Display all settings of the connection profile:

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

3. Display the connection settings in YAML format:

   # nmstatectl show enp7s0

Procedure

1. Create a playbook file, for example ~/ethernet-dynamic-IP.yml, with the following content:

   ---
   - name: Configure the network
     hosts: managed-node-01.example.com
     tasks:
     - name: Configure an Ethernet connection with dynamic IP
       include_role:
         name: rhel-system-roles.network
   
       vars:
         network_connections:
           - name: enp7s0
             interface_name: enp7s0
             type: ethernet
             autoconnect: yes
             ip:
               dhcp4: yes
               auto6: yes
             state: up

2. Run the playbook:

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

Procedure

1. Create a playbook file, for example ~/ethernet-dynamic-IP.yml, with the following content:

   ---
   - name: Configure the network
     hosts: managed-node-01.example.com
     tasks:
     - name: Configure an Ethernet connection with dynamic IP
       include_role:
         name: rhel-system-roles.network
   
       vars:
         network_connections:
           - name: example
             match:
               path:
                 - pci-0000:00:0[1-3].0
                 - &!pci-0000:00:02.0
             type: ethernet
             autoconnect: yes
             ip:
               dhcp4: yes
               auto6: yes
             state: up

   The match parameter in this example defines that Ansible applies the play to devices that match PCI ID 0000:00:0[1-3].0, but not 0000:00:02.0. For further details about special modifiers and wild cards you can use, see the match parameter description in the /usr/share/ansible/roles/rhel-system-roles.network/README.md file.

2. Run the playbook:

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

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

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

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

1. Display the status of the devices and connections:

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

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

   # ping host_name_or_IP_address

Procedure

1. Create the /etc/NetworkManager/conf.d/dhcp-client.conf file with the following content:

   [main]
   dhcp=dhclient

   You can set the dhcp parameter to internal (default) or dhclient.

2. If you set the dhcp parameter to dhclient, install the dhcp-client package:

   # dnf install dhcp-client

3. Restart NetworkManager:

   # systemctl restart NetworkManager

   Note that the restart temporarily interrupts all network connections.

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. Add a connection profile that applies to all interface names starting with enp:

   # nmcli connection add con-name Example connection.multi-connect multiple match.interface-name enp* type ethernet

Verification

1. Display all settings of the single connection profile:

   # nmcli connection show Example
   connection.id:                      Example
   ...
   connection.multi-connect:           3 (multiple)
   match.interface-name:               enp*
   ...

   3 indicates the number of interfaces active on the connection profile at the same time, and not the number of network interfaces in the connection profile. The connection profile uses all devices that match the pattern in the match.interface-name parameter and, therefore, the connection profiles have the same Universally Unique Identifier (UUID).

2. Display the status of the connections:

   # nmcli connection show
   NAME                    UUID                    TYPE     DEVICE
   ...
   Example  6f22402e-c0cc-49cf-b702-eaf0cd5ea7d1  ethernet  enp7s0
   Example  6f22402e-c0cc-49cf-b702-eaf0cd5ea7d1  ethernet  enp8s0
   Example  6f22402e-c0cc-49cf-b702-eaf0cd5ea7d1  ethernet  enp9s0

Procedure

1. Identify the device path. For example, to display the device paths of all interfaces starting with enp, enter :

   # udevadm info /sys/class/net/enp* | grep ID_PATH=
   ...
   E: ID_PATH=pci-0000:07:00.0
   E: ID_PATH=pci-0000:08:00.0

2. Add a connection profile that applies to all PCI IDs matching the 0000:00:0[7-8].0 expression:

   # nmcli connection add type ethernet connection.multi-connect multiple match.path "pci-0000:07:00.0 pci-0000:08:00.0" con-name Example

Verification

1. Display the status of the connection:

   # nmcli connection show
   NAME   UUID     TYPE        DEVICE
   Example      9cee0958-512f-4203-9d3d-b57af1d88466  ethernet  enp7s0
   Example      9cee0958-512f-4203-9d3d-b57af1d88466  ethernet  enp8s0
   ...

2. To display all settings of the connection profile:

   # nmcli connection show Example
   connection.id:               Example
   ...
   connection.multi-connect:    3 (multiple)
   match.path:                  pci-0000:07:00.0,pci-0000:08:00.0
   ...

   This connection profile uses all devices with a PCI ID which match the pattern in the match.path parameter and, therefore, the connection profiles have the same Universally Unique Identifier (UUID).