YvEs2005

1. cd /usr/src/sys/i386/conf/

 vi GENERAL

add 

options    IPFIREWALL			# enables IPFW
options    IPFIREWALL_VERBOSE		# enables logging for rules with log keyword
options    IPFIREWALL_VERBOSE_LIMIT=5	# limits number of logged packets per-entry
options    IPFIREWALL_DEFAULT_TO_ACCEPT # sets default policy to pass what is not explicitly denied
options    IPDIVERT			# enables NAT

and add

options BRIDGE

 

#conf GENERAL

#cd ../../compile/GENERAL

#make depend && make && make install

#reboot 

 

enable bridge :

At this point, to enable the bridge, you have to execute the following commands (having the shrewdness to replace the names of the two network interfaces fxp0and xl0 with your own ones):

# sysctl net.link.ether.bridge_cfg=fxp0:0,xl0:0
# sysctl net.link.ether.bridge.ipfw=1
# sysctl net.link.ether.bridge=1

 

reference :http://www.freebsd.org/doc/en/articles/filtering-bridges/article.html