linux - iptables 端口白名单应该如何设置才能生效？

Question

我设置了 80 和 443 端口只运行白名单 IP 访问，但是发现没有用，实际上任何 IP 都能访问。然后我又测试删除 80 端口的 INPUT 规则，之后依然能访问。明明有 -A INPUT -j DROP。但是 Ben IP 又正常生效 -A INPUT -s 120.26.72.89/32 -j DROP。

    -A INPUT -i lo -j ACCEPT
    -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
    -A INPUT -p icmp -j ACCEPT
    -N whitelist
    -A whitelist -s 103.21.244.0/22 -j ACCEPT
    -A whitelist -s 103.22.200.0/22 -j ACCEPT
    -A whitelist -s 103.31.4.0/22 -j ACCEPT
    -A whitelist -s 104.16.0.0/12 -j ACCEPT
    -A whitelist -s 108.162.192.0/18 -j ACCEPT
    -A whitelist -s 131.0.72.0/22 -j ACCEPT
    -A whitelist -s 141.101.64.0/18 -j ACCEPT
    -A whitelist -s 162.158.0.0/15 -j ACCEPT
    -A whitelist -s 172.64.0.0/13 -j ACCEPT
    -A whitelist -s 173.245.48.0/20 -j ACCEPT
    -A whitelist -s 188.114.96.0/20 -j ACCEPT
    -A whitelist -s 190.93.240.0/20 -j ACCEPT
    -A whitelist -s 197.234.240.0/22 -j ACCEPT
    -A whitelist -s 198.41.128.0/17 -j ACCEPT
    -A whitelist -s 199.27.128.0/21 -j ACCEPT
    -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j whitelist
    -A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j whitelist
    -A INPUT -j DROP
    -A FORWARD -j DROP
    -A OUTPUT -j ACCEPT

Answer 1

Don’t talk about self-built links, let’s talk about normal settings. Why not talk about self-built links? Because I am killing Big Teemo with my roommate (I don’t play games, but killing Big Teemo is really fun), I edited the answer on my mobile phone...
Environment:

server ip: 172.0.0.1
client ip: 127.0.0.2

In fact, it is very simple to allow port 80. If iptables opens the service, the most troublesome thing may be to allow FTP in passive mode

$ iptables -A INPUT -s 127.0.0.2 -p tcp --dport 80 -j ACCEPT
$ iptables -A OUTPUT -d 127.0.0.2 -p tcp --sport 80 -j ACCEPT

Then it is released. Of course, there can be no prohibition rules before matching! The same is true for self-built chains.
Of course, you may need to DROP the entire firewall and then ACCEPT.