I have a chat server running on my local machine that listens to different ports. I want to use the sub-domain of one of my accounts to access it. I intend to manually change the redirect whenever my local machine gets a different ip address.

So: chat.example.com:123 would redirect to dynamic.ip.address:123

I am trying to accomplish this with .htaccess and RewriteRule I have tried:

RewriteEngine on
RewriteRule ^(.*) http://dynamic.ip.address/ [L, R=302]

but this doesn't work. When I try chat.example.com:123 nothing happens. When I input chat.example.com into the web browser, I get dynamic.ip.address

Is .htaccess the right tool for this?

I am using a simple web host that gives me ssh access, but not much more.