1、检查是否有安装iptables, 我是在root账号下执行的,如果非root有些请加上sudo
# 检查
root@cocosum:~# which iptables
/sbin/iptables
root@cocosum:~# whereis iptables
iptables: /sbin/iptables /etc/iptables /usr/share/iptables /usr/share/man/man8/iptables.8.gz
# 说明有安装iptables
2、如果没有安装iptables则需要安装
# 进行安装
sudo apt-get install iptables
3、如果安装了需要配置防火墙规则,我这里自己创建一个防火墙规则
# 创建防火墙规则的文件
root@cocosum:~# vi /etc/iptables
# 添加下面的规则
*filter
:INPUT DROP [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:syn-flood - [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 3306 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 8080 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 7070 -j ACCEPT
-A INPUT -p icmp -m limit --limit 100/sec --limit-burst 100 -j ACCEPT
-A INPUT -p icmp -m limit --limit 1/s --limit-burst 10 -j ACCEPT
-A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j syn-flood
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A syn-flood -p tcp -m limit --limit 3/sec --limit-burst 6 -j RETURN
-A syn-flood -j REJECT --reject-with icmp-port-unreachable
COMMIT
4、保存规则
root@cocosum:~# iptables-save > /etc/iptables
5、创建一个脚本, 为了每次重启系统, iptables防火墙自动启动
# 直接创建,目的是为了系统每次重启自动加载
root@cocosum:~# vi /etc/network/if-pre-up.d/iptables
# 内容
#!/bin/bash
iptables-restore < /etc/iptables
# :wq保存
6、给添加的脚本有执行的权限
root@cocosum:~# chmod +x /etc/network/if-pre-up.d/iptables
7、查看iptables;直接iptables -L ,和centos 差不多
root@cocosum:~# iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:http
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:https
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:mysql
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:http-alt
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:7070
ACCEPT icmp -- anywhere anywhere limit: avg 100/sec burst 100
ACCEPT icmp -- anywhere anywhere limit: avg 1/sec burst 10
syn-flood tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/SYN
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain syn-flood (1 references)
target prot opt source destination
RETURN tcp -- anywhere anywhere limit: avg 3/sec burst 6
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable