Scenario

Your friend wants to play a game with you on your server. Both of you are at your respective homes, connected to the Internet. You need to configure your SOHO (Small Office, Home Office) router to port forward HTTP requests to your server so that your friend can access the game lobby web page.

Packet Tracer - Configuring Port Forwarding on a Linksys Router Instructions

Packet Tracer - Configuring Port Forwarding on a Linksys Router - PKA