man > VETH(4)

veth(4)                               Kernel Interfaces Manual                               veth(4)

NAME
       veth - Virtual Ethernet Device

DESCRIPTION
       The veth devices are virtual Ethernet devices.  They can act as tunnels between network name‐
       spaces  to create a bridge to a physical network device in another namespace, but can also be
       used as standalone network devices.

       veth devices are always created in interconnected pairs.  A pair can  be  created  using  the
       command:

           # ip link add <p1-name> type veth peer name <p2-name>

       In the above, p1-name and p2-name are the names assigned to the two connected end points.

       Packets  transmitted  on one device in the pair are immediately received on the other device.
       When either device is down, the link state of the pair is down.

       veth device pairs are useful for combining the network facilities of the kernel  together  in
       interesting  ways.  A particularly interesting use case is to place one end of a veth pair in
       one network namespace and the other end in another network namespace, thus allowing  communi‐
       cation between network namespaces.  To do this, one can provide the netns parameter when cre‐
       ating the interfaces:

           # ip link add <p1-name> netns <p1-ns> type veth peer <p2-name> netns <p2-ns>

       or, for an existing veth pair, move one side to the other namespace:

           # ip link set <p2-name> netns <p2-ns>

       ethtool(8) can be used to find the peer of a veth network interface, using commands something
       like:

           # ip link add ve_A type veth peer name ve_B   # Create veth pair
           # ethtool -S ve_A         # Discover interface index of peer
           NIC statistics:
                peer_ifindex: 16
           # ip link | grep '^16:'   # Look up interface
           16: ve_B@ve_A: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc ...

SEE ALSO
       clone(2), network_namespaces(7), ip(8), ip-link(8), ip-netns(8)

Linux man-pages 6.7                          2023-10-31                                      veth(4)