Comment 13 for bug 239360

I found an argument why we should support any port, even within Firefox.

Example: The IRC client Chatzilla that can be installed as an addon to Firefox. Server irc.mozilla.org operates an SSL service on port 6697.

While this port number is not blocked by the netwerk backend, I noticed it takes a long time until the dialog finally reports the certificate details. I guess this is related to our attempt to attempt an http procotol request on a server that really uses a different protocol. The server probably keeps the connection up for a while, waiting for the kind of protocol message it expects... Not all protocols might time out quickly.