Are there any features of opening ports on Centos 6?

Question

iptables

I can’t find a manual for setting up port opening on Centos 6, a lot of things have been written, but for a beginner, as for me, something important is clearly missed, because no matter how I enter commands, I can’t open new ports, close those that are .. .... tell me what could be the problem *?
look at these stats! and so it’s not possible to close what is, not to open a new one ....
help pliz!
https://2ip.ua/en/services/ip-service/port-check?h...
in particular, I'm trying to close port 3306, 22 and open 2106.... so the wrong ones don't close and 2106 doesn't open. ...
port 2106 is needed to run the lineage interlude server! server log swears at opening coketa
[12.08.18 12:50:02] Listening for GameServers on 127.0.0.1:9014
[08/12/18 12:50:02 PM] FATAL: Failed to open server socket. Reason: Cannot assign requested address
java.net.BindException: Cannot assign requested address

Answer 1

I’ll answer my own question myself ... it turns out that the port is open or not, the site will show if only you have already launched some application and it wants to work on this port .... in general, I didn’t set up the server correctly, therefore I couldn’t figure out the ports)) )