暂时只会两种方法：
1.
Freebsd# ifconfig
lnc0: flags=108843 mtu 1500
inet6 fe80::20c:29ff:fe7b:3dcd%lnc0 prefixlen 64 scopeid 0x1
inet 10.0.0.199 netmask 0xffffff00 broadcast 10.0.0.255
ether 00:0c:29:7b:3d:cd
plip0: flags=108810 mtu 1500
lo0: flags=8049 mtu 16384
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
inet 127.0.0.1 netmask 0xff000000
Freebsd# ifconfig lnc0 10.0.0.111 netmask 255.255.255.0
这种方法即时生效，但是重启机器后，信息不保留。
2.
打开/etc/rc.conf
加入或修改：ifconfig_网卡名称="inet x.x.x.x netmask x.x.x.x"
ifconfig_lnc0="DHCP"
之后 reboot 或 #sh /etc/rc
Freebsd# more /etc/rc.conf
# -- sysinstall generated deltas -- # Thu Oct 12 09:37:56 2006
# Created: Thu Oct 12 09:37:56 2006
# Enable network daemons for user convenience.
# Please make all changes to this file, not to /etc/defaults/rc.conf.
# This file now contains just the overrides from /etc/defaults/rc.conf.
defaultrouter="10.0.0.1"
hostname="Freebsd.lzyq.org"
ifconfig_lnc0="inet 10.0.0.199 netmask 255.255.255.0"
keymap="us.iso"
linux_enable="YES"
sshd_enable="YES"
Freebsd#
这种方法，信息永久保留，但是修改完需要重启机器。
如果要设置多IP地址可用别名方式作修改如下
ifconfig_lnc0="inet 10.0.0.199 netmask 255.255.255.0"
改为
ifconfig_lnc0_alias0="inet 10.0.0.198 netmask 255.255.255.0"
ifconfig_lnc0_alias1="inet 10.0.0.197 netmask 255.255.255.0"
