Hello Roberts71, welcome to LQ.
Please be patient, it's not useful to ask similar questions in two different posts. If you wanted to change the way your first post was stated, you could have edited it.
That said, I feel hard to answer this question, as you say nothing about the way the players communicate with the server. If, say, for now their box is allocated an IP by a DHCP
server, you should make this server visible on the Internet. For that it should have a fixed public IP associated with a domain name, I guess. The way you can get that differ upon the way the server is itself connected to the Internet. If it his a self hosted box, or a dedicated hosted server there should be no problem. if it his hosted by an ISP, this ISP should tell you what to do, if this feature is included in your contract.