I may have a solution, maybe.
I posted my issue in this thread on page 12, were I said that I was fine before patch 4.01 and then constant disconnects during battle after that patch. I could however go AFK and remain connected without issue.
Anyway, during the long period I went AFK because I got tired of getting the boot, I remembered the Stormblood System Requirements detailing something about connection ports which I thought was weird, since you don't usually see specific ports in any system requirements.
So I looked up the SB system requirements again and saw this text and these numbers:
Quote:
If you are using a router, please set up your ports so that the below packets can pass through.
[Ports that may be used]
TCP:80, 443, 54992~54994, 55006~55007, 55021~55040
I went into my router settings and found a "Services" tab that allowed me to input these details above. The "80" and "443" can be ignored(at least for me) but as you can see below, I input the other longer port numbers and created these.
Screenshot of my Router Settings for reference
http://i.imgur.com/XcWc8QD.png
Now this might be a coincidence, since I was AFK for several hours before coming back and trying this out. But after inputting the above info and rebooting my router. I started up FFXIV again and played for a few hours. I was able to do quests, FATEs and battle in general without issue.
I refrained from posting about this yesterday because I wasn't sure this was a possible solution. So I decided to wait to see what the next day would be like. And again this might just be some coincidence, but today I have had no issues whatsoever, so of course I decided to post here out of curiosity to see if this helps anyone else.