Which ports are used on a ISPConfig 3 server and shall be open in the firewall?
Here is a list of ports that are used commonly on ISPConfig 3 servers. If you don't have all services installed or if you e.g. don't want to connect to MySQL from external servers, then close the unused or unwanted ports. TCP ports 20 - FTP Data 21 - FTP Command 22 - SSH 25 ... Read more