free# sysctl net.link.ether.bridge.enable=1
net.link.ether.bridge.enable: 0 -> 1
free# sysctl net.link.ether.bridge_cfg=vr0,tap0
net.link.ether.bridge_cfg:  -> vr0,tap0
free# kldstat
Id Refs Address    Size     Name
 1   13 0xc0400000 63070c   kernel
 2   16 0xc0a31000 568dc    acpi.ko
 3    1 0xc19e6000 2000     fire_saver.ko
 4    1 0xc1a01000 15000    linux.ko
 5    1 0xc1bfe000 4000     if_tap.ko
 6    1 0xc1c02000 8000     if_bridge.ko
 7    1 0xc1c0a000 7000     bridge.ko
 8    1 0xc1c44000 1b000    kqemu.ko
free# ifconfig -a
vr0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::20a:e6ff:fe87:2500%vr0 prefixlen 64 scopeid 0x1
        inet 172.20.10.41 netmask 0xffffff00 broadcast 172.20.10.255
        ether 00:0a:e6:87:25:00
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST,NEEDSGIANT> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet6 ::1 prefixlen 128
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
        inet 127.0.0.1 netmask 0xff000000
tap0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::2bd:ffff:fe22:200%tap0 prefixlen 64 scopeid 0x4
        inet 0.0.0.0 netmask 0xff000000 broadcast 0.255.255.255
        ether 00:bd:ff:22:02:00
        Opened by PID 556
free#