Debian邮件服务器防火墙配置技巧

sudo apt-get update
sudo apt-get install iptables

sudo iptables -L

*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -p tcp --dport 25 -j ACCEPT
-A INPUT -p tcp --dport 143 -j ACCEPT
-A INPUT -p tcp --dport 110 -j ACCEPT
-A INPUT -j LOG --log-prefix "iptables denied: " --log-level 4
-A INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT

sudo iptables-save > /etc/iptables.rules

sudo iptables-restore < /etc/iptables.rules

sudo sh -c 'echo "/sbin/iptables-restore < /etc/iptables.rules" > /etc/network/if-pre-up.d/iptables'
sudo chmod +x /etc/network/if-pre-up.d/iptables

sudo apt-get update
sudo apt-get install firewalld

sudo systemctl start firewalld
sudo systemctl enable firewalld

*filter
:public - [0:0]
:public6 - [0:0]
:work - [0:0]
:internal - [0:0]
:external - [0:0]
:dmz - [0:0]
:trusted - [0:0]

# Allow traffic on ports 25, 143, and 110 for mail services
-A public -p tcp --dport 25 -j ACCEPT
-A public -p tcp --dport 143 -j ACCEPT
-A public -p tcp --dport 110 -j ACCEPT

sudo firewall-cmd --reload

#!/bin/sh
/sbin/firewall-cmd --restore < /etc/firewalld/zones