Question on port conflicts

Question

If two applications require the same port, is it a reliable option to change the port number used by one of the apps to fix the conflict? Also, how do I know that the number above 4541, for example, is a port (is there a complete list)?

This is hypothetical but in the past I've had port conflicts and wondered how best these can be resolved.

Thanks

Answer 1

Making one of the applications use a different port will resolve the conflict, but there may be other reasons why it won't do which are beyond the scope of this question.

/etc/services contains a list of known ports and services.

Answer 2

The IANA port numbers list contains the definitive list of ports. The end of the list contains a list of the relevant RFCs. The list states

The Dynamic and/or Private Ports are those from 49152 through 65535.

It is common for sites to implement private services on ports that are not listed, or listed to other services. This results in problems such as you have encountered.

Answer 3

Changing the port of one of the server applications will resolve the conflict, but you then need to ensure that any client application that needs to connect to the server knows that it should use the new port number instead of the original, default number.