Why do SSO providers like Ping Federate run on ports that aren't well-known like 9031. Does this enhance security? It seems like it just increases connectivity issues in organizations with strict firewall rules.
That's just a default semi-random port so that it doesn't clash with existing services on the same machine and is a high port so that the server can run under a non-privileged user account.
For production usage one would typically change it to 443 and/or run a reverse-proxy/loadbalancer in front of the SSO server (on port 443).