Then for every server you have to create an SRV. For example "server1.domain.com", "server2.domain.com" etc, change the Port but put Target to the same address.
If server1 has port 25900, then put the port in the server1 SRV record to 25900.
Are you saying that every port on a server should I do that?
If yes I already did as you can see in the image above, however if I disconnect the DNS server can not connect to the server, can you send me an example of how it should be done?