Manual Pages  — EPAIR

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

if_epair_load="YES"

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.