Ubuntu配置防火墙iptables重启生效（常见iptables的用法记录）

Ubuntu配置防火墙iptables重启生效（常见iptables的用法记录）

基于服务器的安全考虑，我们需要在Ubuntu 18.04环境中进行配置iptables防火墙，这里老蒋简单的记录iptables的常规用法。一般我们都是在需要服务器的ROOT权限下进行的，有些服务器环境默认是安装过的，我们需要检查到底是否有安装，如果有安装过，直接就添加防火墙规则。

第一、检查是否安装iptables

# 检查
# which iptables
/sbin/iptables
# whereis iptables
iptables: /sbin/iptables /etc/iptables /usr/share/iptables /usr/share/man/man8/iptables.8.gz

第二、安装iptables

如果没有安装的话，我们则需要安装。

# 进行安装
sudo apt-get install iptables

第三、如果安装过我们创建规则

vi /etc/iptables

我们添加规则。

*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

然后保存规则

iptables-save > /etc/iptables

第四、创建规则确保重启也执行iptable规则

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

第四、创建规则确保重启也执行iptable规则

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

添加：

iptables-restore < /etc/iptables

保存退出。

第五、查看防火墙规则

iptables -L

这里我们可以看到所有的防火墙设置。

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

一般情况下，就这么用的。具体的iptables的配置，我们可以根据需要进行端口设置。