往FreeBSD新增IP的方法：

vi /etc/rc.conf

First line is the main ip address + subnet mask
Second line and thereafter use the 'alias' in the config line and netmask of
255.255.255.255 and proper broadcast ip.

ALso, may not be fxp0, might be sis0, rltk0, etc..
ifconfig_fxp0="inet 10.10.10.34 netmask 255.255.255.248"
ifconfig_fxp0_alias0="inet 10.10.10.35 netmask 255.255.255.255"
ifconfig_fxp0_alias1="inet 10.10.10.36 netmask 255.255.255.255"
ifconfig_fxp0_alias2="inet 10.10.10.37 netmask 255.255.255.255"

etc..

Also you can run /stand/sysconfig
Choose Configure, Networking, Interfaces, then nic card ( fxp0, rltk, dlink,
rl0, vne, etc...)