服務器采用Ubuntu作為操作系統，兩塊網卡，一塊接外網（eth0），一塊接內網（eth1）。采用shorewall作為防火牆。
配置網卡：
sudo vi /etc/network/interfaces
Ubuntu下設置shorewall防火牆
服務器采用Ubuntu作為操作系統，兩塊網卡，一塊接外網（eth0），一塊接內網（eth1）。采用shorewall作為防火牆。
配置網卡：
sudo vi /etc/network/interfaces
------------------------------------------------
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# This is a list of hotpluggable network interfaces.
# They will be activated automatically by the hotplug subsystem.
mapping hotplug
script grep
map eth0
# The primary network interface
iface eth0 inet static
address 192.168.2.250
netmask 255.255.255.0
network 192.168.2.0
broadcast 192.168.2.255
gateway 192.168.2.1
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 202.96.209.6
auto eth1
iface eth1 inet static
address 192.168.10.254
netmask 255.255.255.0
network 192.168.10.0
broadcast 192.168.10.255
1、安裝shorewall
sudo apt-get install shorewall
2、拷貝配置文件
sudo cp /usr/share/shorewall/modules /etc/shorewall
sudo cp /usr/share/doc/shorewall/default-config/policy /etc/shorewall/
sudo cp /usr/share/doc/shorewall/default-config/nat /etc/shorewall/
sudo cp /usr/share/doc/shorewall/default-config/zones /etc/shorewall/
sudo cp /usr/share/doc/shorewall/default-config/maclist /etc/shorewall/
sudo cp /usr/share/doc/shorewall/default-config/blacklist /etc/shorewall/
sudo cp /usr/share/doc/shorewall/default-config/interfaces /etc/shorewall/interfaces
sudo cp /usr/share/doc/shorewall/default-config/rules /etc/shorewall/rules
sudo cp /usr/share/doc/shorewall/default-config/hosts /etc/shorewall/hosts
sudo cp /usr/share/doc/shorewall/default-config/masq /etc/shorewall/masq
3、配置網卡
sudo vi /etc/shorewall/interfaces
在倒數第二行，也就是在 “#LAST LINE —— ADD YOUR ENTRIES BEFORE THIS ONE —— DO NOT REMOVE” 這一行之後加上：
net eth0 detect
loc eth1 detect
4、配置網絡別名
sudo vi /etc/shorewall/zones
在倒數第二行，也就是在 “#LAST LINE —— ADD YOUR ENTRIES BEFORE THIS ONE —— DO NOT REMOVE” 這一行之後加上：
net Net Internet
loc Local Local Networks
5、配置IP偽裝，也就是透明代理
sudo vi /etc/shorewall/masq
在倒數第二行，也就是在 “#LAST LINE —— ADD YOUR ENTRIES BEFORE THIS ONE —— DO NOT REMOVE” 這一行之後加上：
eth0 eth1
6、配置策略
sudo vi /etc/shorewall/policy
在#LAST LINE —— DO NOT REMOVE這一行最後加上：
loc net ACCEPT
net all DROP info
all all REJECT info
7、配置防火牆規則
sudo vi /etc/shorewall/rules
在倒數第二行，也就是在 “#LAST LINE —— ADD YOUR ENTRIES BEFORE THIS ONE —— DO NOT REMOVE” 這一行後加上：
#incoming traffic （由 internet 去 firewall）
AllowSSH net fw
AllowDNS net fw
AllowWeb net fw
AllowSMB net fw
AllowNNTP net fw
AllowNTP net fw
AllowRdate net fw
AllowSMTP net fw
DropPing net fw
#outgoing traffic （由 firewall 去 internet）
AllowWeb fw net
AllowDNS fw net
AllowSMTP fw net
AllowSMB fw net
AllowSMTP fw net
AllowNNTP fw net
AllowNTP fw net
AllowRdate fw net
AllowSSH fw net
#open special ports
ACCEPT net fw tcp 9980
8、修改 shorewall.conf 自動開啟 IP 轉發
sudo gedit /etc/shorewall/shorewall.conf
查找到：
IP_FORWARDING=Keep
修改為：
IP_FORWARDING=On
# 保存關閉文件
9、修改 /etc/default/shorewall 自動運行防火牆
sudo vi /etc/default/shorewall
查找到：
startup=0
修改為：
startup=1
10、啟動防火牆
sudo shorewall start
11、至此防火牆配置完成