which tcp port to use?

[cbodapati]

Hi,

 

I wrote a small tcp test server (in php) to process some custom messages. I am not sure which port to open. What are the factors I should consider before finalizing a port number. Does this invite any security threats?

 

Where can I find answers to these questions?

 

any help appreciated.

 

thanks

[justsomeguy]

Look for a list of commonly-used ports and avoid using anything that something common would use. It will probably be a 5-digit port.

Does this invite any security threats?

Open ports in general have security implications, but not so much the specific port number. The security is all in your application that handles the traffic.

[cbodapati]

Thank you very much for the information.

[Don E]

Here is a good list I check out for used ports: http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers