[s0xxx]

http://www.freebsd.org/cgi/cvsweb.cg...-cvsweb-markup

http://www.freebsd.org/cgi/cvsweb.cg...-cvsweb-markup

See man if_bridge(4):

The bridge can tunnel Ethernet across an IP internet using the EtherIP
protocol. This can be combined with ipsec(4) to provide an encrypted
connection. Create a gif(4) interface and set the local and remote IP
addresses for the tunnel, these are reversed on the remote bridge.