I aggree with your points and I´m familiar with IP stuff, it´s my daily work. I guess that Bungie is using GRE to tunnel traffic, no classic VPN connection is established between PS4 and Bungie. GRE btw is also used for DOS prevention. Let my explain the situation a bit further: Your homenetwork is setup with 2 vlans, 192.168.0.x/24 and 192.168.2.x/24 (Standard ISP hardware/router) Bungie tunnels 192.168.0.x host-addresses to your PS4. As soon as these networks are directly connected to your router (which is in our example), your router won´t ever use the WAN interface as gateway for returning the connection to the bungie host, the traffic is routed locally. I´m 100% sure that there´s no IP conflict, I don´t own the host-addresses. The host-addresses were directly attached to the PS4 flow. My public IP is directly sitting on my edge device, no ISP equipment in between. No layer 8 problem here ;)

All makes sense, and my level of understanding your understanding (for lack of a better term) is more complete: you'd be surprised how many people in a code factory don't understand any level of networking, so I always have to make assumptions round that. In my case, I have a much different internal vlan setup, -but- I am one of the people that understand it well enough to know why it's a good / not good thing to do; most people are in the plug and play category. Depending on your ISP and equipment, this is a very real issue. I wish I could give everyone the advice I would give myself, which is manually manage your vlan (and all the rest of your network infrastructure), but it's not realistic. Perhaps a solution until Bungie gets their networking protocols in order (release dat e is currently slated for the 5th of Never) would be for people like yourself and me to work on a barebones level guide to setting up networks at home for the average user: I know there is no one and done guide, due to the different end-use devices and ISP equipment, but it might make some difference. On the other hand, if you're like me, I'll sit down to outline something like that, and then immediately have 15 IP phones deposited on my desk for provisioning to a new office location, before the VPN and tunneling are even worked out...and Mitel 53xx series going back to a Mitel 5000 ICP at that...it's gross.

coding vs networking - these are 2 different scopes. I have basic knowledge of some languages, but wouldn´t be able to write large code. :) I guess we have a non-standard deployment at home. :D Plug & Play is for users without - or minimal knowledge, so nearly everyone can setup a small network at home. Manually desgining and configuring the whole network would assume some basic knowledge about networking, which the majority of all the internet users doesn´t have - therefore plug&play. Writing a guide would be a good start, but as you stated, this is not an easy task, as different needs, devices, and so on. Maybe one time ... :) Back to the problem, it can affect anyone here, as those private IP ranges bungie is using, are pretty common on default configurations - not only in ISP default configs. I hope we will get some official response here...