Question

I want to allow a new application server to access mysql on current 3306 port, I used the following command

iptables -I INPUT 13 -s 111.222.333.444 -p tcp --dport 3306 -j ACCEPT

It is working as expected. I can check if the rule is set as expected.

iptables -nvL
4 240 ACCEPT tcp -- * * 111.222.333.444 0.0.0.0/0 tcp dpt:3306

How do I revoke the access?

Answer 1

You can delete the rule using:

iptables -D INPUT 13

You can see man iptables for more options.

Please, note that this assumes that default INPUT policy is DROP. Otherwise, you need to add an explicit DROP rule.

If you want to deny remote access to mysql server for all IPs, you can change the listen address to be 127.0.0.1.