Can I use another port other than 443 for SSL communication?

Question

I have an application that communicates via SSL, however, Port 443 is already in use by an IIS instance on that same server. Can I use another port other than 443 for SSL communication?

Answer 1

SSL is in no way tied to a single port value; in fact, as a protocol, it can be used over any transport medium, as long as that medium provides a bidirectional stream for arbitrary bytes.

In a Web context, you can use any port other than 443, provided that you specify it in the URL: https://www.example.com:7342/foobar.html

Note that there are some networks (especially some free WiFi access points) that don't allow traffic over other ports than 443 or 80; which means that using a port other than 443, though perfectly standard and supported, may imply some practical usage restrictions.

Answer 2

You can use (nearly) every port, which is not used, for SSL communication. The question is: Did you mean that someone enters https://... and your service is not on port 443? Than it is not directly possible. Modern browsers use the prefix https:// to connect to serveraddress:443 (if no port is present). Similar to http:// which connects to serveraddress:80.

Answer 3

On Apache you can do this on the same port: http://www.digicert.com/ssl-support/apache-multiple-ssl-certificates-using-sni.htm

And on IIS: http://www.iis.net/learn/get-started/whats-new-in-iis-8/iis-80-server-name-indication-sni-ssl-scalability