[skydhash]

Maybe the joke has gotten too far, but the point that most people have been trying to say is that the issue that the OP is trying to solve has been solved for years. It's called a reverse proxy. Doing the configuration automatically like OP does does not alter the fact that it is a reverse proxy. `/etc/services` serve a different purpose.

Also URL parsing is a completely different matter. Browsers are primarily an HTTP(s) client. If you do not mention the ":port", it will try to connect to 80 (HTTP) or HTTPS (443). Because that the default ports for a web server. Other services have different port. So if your URL has the ftp scheme, the default port would be 21.