How to allow incoming connections only for a few IPs on a specific port?

Question

linux

Hello.
Please tell me how to allow incoming connections only for a few IP addresses on a specific port, and forbid all others from outside.
In other words, there is a certain MySQL database server and three IP addresses (for example: xxxx, yyyy, zzzz ). So, you need to close access to port 3306 for everyone, except for these addresses. And also allow one of them to connect via SSH.

Answer 1

in this case, you can configure the rules you need using the iptables utility to configure firewall rules.
For example, you can block access to port 3306 from all ips with the command
`iptables -A INPUT -p tcp --dport 3306 -j DROP`
Then you can add permissions for individual ip with the command
`iptables -A INPUT -s -p tcp - -dport 3306 -j ACCEPT`