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veth(4) Linux Programmer's Manual veth(4)

NAME

     veth - Virtual Ethernet Device

DESCRIPTION

     The veth devices are virtual Ethernet devices.  They can act as tunnels
     between network namespaces 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 devices 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 first  creates  the
     veth  device  as above and then moves one side of the pair to the other
     namespace:

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

     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 sta-
         tistics:
              peer_ifindex: 16 # ip link | grep '^16:'   # Look up interface
         16: ve_B@ve_A: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc ...