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?

3 Answers 3


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.


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.

  • Thanks for your response. The other services using SSL is a security tool, so it is not related specifically to using "https://.."
    – dandaman12
    Aug 1, 2014 at 14:16

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

  • 1
    Not answering the question as such but answering the spirit of it!
    – Andy Boura
    Aug 1, 2014 at 14:07
  • Great info! I didn't realize IIS 8.0 resolved the multi cert issue / multi IP addresses requirement.
    – k1DBLITZ
    Aug 1, 2014 at 14:41

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