Debian Iptables防火墙配置

iptables很强大，这只是介绍我小小的fllow debian wiki  然后简单的设置了下iptables，以后再根据需求具体设置

首先 (查看当前iptables配置，我装的debian默认安装了)

sudo iptables -L

如果没配置过的话，输出是（什么作用都没起到）

 Chain INPUT (policy ACCEPT)
 target     prot opt source               destination

 Chain FORWARD (policy ACCEPT)
 target     prot opt source               destination

 Chain OUTPUT (policy ACCEPT)
 target     prot opt source               destination

接下来开始配置rules ,在新建的文件里面写配置

vim /etc/iptables.test.rules

然后输入

*filter

# Allows all loopback (lo0) traffic and drop all traffic to 127/8 that doesn‘t use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT

# Accepts all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

# Allows all outbound traffic
# You could modify this to only allow certain traffic
-A OUTPUT -j ACCEPT

# Allows HTTP and HTTPS connections from anywhere (the normal ports for websites)
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT

# Allows SSH connections
# The --dport number is the same as in /etc/ssh/sshd_config
-A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT

# Now you should read up on iptables rules and consider whether ssh access
# for everyone is really desired. Most likely you will only allow access from certain IPs.

# Allow ping
#  note that blocking other types of icmp packets is considered a bad idea by some
#  remove -m icmp --icmp-type 8 from this line to allow all kinds of icmp:
#  https://security.stackexchange.com/questions/22711
-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT

# log iptables denied calls (access via ‘dmesg‘ command)
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7

# Reject all other inbound - default deny unless explicitly allowed policy:
-A INPUT -j REJECT
-A FORWARD -j REJECT

COMMIT

上面是官方给的配置实例，具体参数有说明

这里有一个介绍参数的https://help.ubuntu.com/community/IptablesHowTo

我实际只留下四条，以后根据自己需求再改吧

配置文件写好之后就可以运行下面的命令来使用这些rules

sudo iptables-restore < /etc/iptables.test.rules

然后可以

iptables -L 查看配置前后不同的地方

最后设置开机启动（开机将写好的rules激活）

vim /etc/network/if-pre-up.d/iptables

写入..

 #!/bin/sh
 sudo /sbin/iptables-restore < /etc/iptables.up.rules

然后

sudo chmod +x /etc/network/if-pre-up.d/iptables

可以啦