Hello World

FreeBSD + IPFW 當 NAT 供內部電腦上網

測試環境
client pc
ip: 10.2.3.100/255.255.255.0
gate way: 10.2.3.254

freebsd host:
os: FreeBSD 9.3-RELEASE x64
em0: x.x.x.x/255.255.255.0 (internet ip)
em1: 10.2.3.254/255.255.255.0

step1:
# cd /usr/src/sys/amd64/conf
將以下幾行加入 kernel , 並重新compile
options IPFIREWALL
options IPFIREWALL_VERBOSE
options IPFIREWALL_VERBOSE_LIMIT=5
options IPFIREWALL_DEFAULT_TO_ACCEPT
options IPDIVERT

step2:
編輯/etc/rc.conf
firewall_enable="YES"
firewall_type="OPEN"
natd_interface="em0" ##這裡是外部ip網卡的代號
natd_enable="YES"
gateway_enable="YES"

step3:
重開機，如果設定正常的話，在內部網路的client應該都可以透過freebsd上網了~

step4: (可省略)
# ipfw show
檢查是否有這一行
00050 34679 4765350 divert 8668 ip4 from any to any via em0