查看“Debian配置iptables”的源代码

=iptables=
Debian默认已经安装iptables，查看规则iptables -L默认允许所有出入，这是非常不安全的，因此需要对规则进行调整。

编辑配置文件：
 vim /etc/iptables.up.rules

添加下面的规则，请根据实际情况调整：
<pre>
*filter

#ssh
-A INPUT -p tcp --dport 22 -j ACCEPT
# 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 80 -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  </pre>

激活规则：
 iptables-restore < /etc/iptables.test.rules

开机自动加载规则
编辑配置
 vi /etc/network/if-pre-up.d/iptables

添加如下内容
<pre>
#!/bin/sh
 /sbin/iptables-restore < /etc/iptables.up.rules</pre>

添加执行权限
 chmod +x /etc/network/if-pre-up.d/iptables

保存规则到主配置文件：
 iptables-save > /etc/iptables.up.rules

=参考=
[[大话iptables]]

[[Iptables模块]]

[https://www.centos.bz/2017/10/debian%E9%85%8D%E7%BD%AEiptables/ Debian配置iptables]

https://wiki.debian.org/iptables

[[category:debian]] [[category:Security]]  [[category:ops]]