Originally Posted by
worldofneil
You don't need to forward any ports. That's only needed when something is trying to access a service on your computer and with FFXIV (and most games), you're running a client connecting to their server, not the other way round so if you actually forwarded any ports to your computer, you'd just be creating potential security risks, you certainly don't need to do that to run the game.
The WiFi is likely shutting down because possibly (am I mean no offence) the router isn't very good quality and doesn't handle the packets streaming through it (I've seen this first hand with cheap access points at my work which will crash when too much traffic goes through them). The other thing it might be is that your router has non-standard WiFi settings turned on (like "Turbo mode" to boost WiFi speed or other similar name dthings, but they aren't a standard thing and is specific to certain manufacturers) or it might be some sort of WiFi protection mode where it intentionally shuts down if if it detects possible security risks (DoS filters etc).