Yes, you can do it on your server with a simple iptable rule.
I'm a little rusted, but something like this should work.
iptables -t nat -A PREROUTING -d [your IP] -p tcp --dport 11500 -j DNAT --to-destination [your IP:443]
You can find more information searching for "iptables dnat". What you are saying here is: in the prerouting table (ie: before we decide what to do with this packet) tcp connections to my IP at the port 11500 must be forwarded to my IP at port 443.