Chapter 22. Creating a dummy interface

As a Red Hat Enterprise Linux user, you can create and use dummy network interfaces for debugging and testing purposes. A dummy interface provides a device to route packets without actually transmitting them. It enables you to create additional loopback-like devices managed by NetworkManager and makes an inactive SLIP (Serial Line Internet Protocol) address look like a real address for local programs.

22.1. Creating a dummy interface with both an IPv4 and IPv6 address using nmcli

You can create a dummy interface with various settings. This procedure describes how to create a dummy interface with both an IPv4 and IPv6 address. After creating the dummy interface, NetworkManager automatically assigns it to the default public firewall zone.

Note

To configure a dummy interface without IPv4 or IPv6 address, set the ipv4.method and ipv6.method parameters to disabled. Otherwise, IP auto-configuration fails, and NetworkManager deactivates the connection and removes the dummy device.

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

Additional resources

  • The nm-settings(5) man page