epair — A pair of virtual back-to-back connected Ethernet interfaces

       The  epair  interface was written by Bjoern A. Zeeb, CK Software GmbH, under sponsorship from the FreeBSD
       Foundation.

Debian                                           March 18, 2015                                         EPAIR(4)

       The epair is a pair of Ethernet-like software interfaces, which are connected back-to-back with a virtual
       cross-over cable.

       Each  epair  interface pair is created at runtime using interface cloning.  This is most easily done with
       the ifconfig(8) create command or using the cloned_interfaces variable in rc.conf(5).  While for  cloning
       you  only  give  either epair or epair<n> the epair pair will be named like epair<n>[ab].  This means the
       names of the first epair interfaces will be epair0a and epair0b.

       Like any other Ethernet interface, an epair needs to have a network address.  Each epair will be assigned
       a locally administered address by default, that is only guaranteed to be unique within one network stack.
       To change the default addresses one may use the SIOCSIFADDR ioctl(2) or ifconfig(8) utility.

       The basic intent is to provide connectivity between two virtual network stack instances.  When  connected
       to an if_bridge(4), one end of the interface pair can also be part of another (virtual) LAN.  As with any
       other Ethernet interface, epair can have a vlan(4) configured on top of it.

       The epair interface first appeared in FreeBSD 8.0.

       epair — A pair of virtual back-to-back connected Ethernet interfaces

ioctl(2), altq(4), bpf(4), if_bridge(4), vlan(4), loader.conf(5), rc.conf(5), ifconfig(8)

       To compile this driver into the kernel, place the following line in your kernel configuration file:

             deviceepair

       Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

             if_epair_load="YES"