Matt Hoppes raises an interesting question,

At the risk of this being off-topic, in the latest call of duty games I've played, their UDP-NAT-breaking algorithm seems to work rather well and should function fine even behind CGNAT. Ironically turning on upnp makes this *worse*, because when their algorithm probes to see what ports to use, upnp sends all traffic from the "magical xbox port" to one box instead of letting NAT control the ports. This does cause problems when multiple xboxes are behind one NAT doing upnp. If upnp is on and both xboxes are fully powered off and then turned on one at a time, things do work. But when upnp is off everything works w/o having to do that.

There are many other games and many CPE NAT boxes that may do horrible things, but CGNAT by itself shouldn't cause problems for any recent device / gaming system.

It is true that I've yet to see any FPS game use ipv6. I assume that's cuz they can't count on users having v6, so they have to support v4, and it wouldn't be worth their while to have their gaming host support dual-stack. just a guess there

-- Dan



On Sun, Sep 27, 2020 at 7:29 PM Mike Hammett <nanog@ics-il.net> wrote:
Actually, uPNP is the only way to get two devices to work behind one public IP, at least with XBox 360s. I haven't kept up in that realm.



-----
Mike Hammett
Intelligent Computing Solutions

Midwest Internet Exchange

The Brothers WISP

From: "Matt Hoppes" <mattlists@rivervalleyinternet.net>
To: "Darin Steffl" <darin.steffl@mnwifi.com>
Cc: "North American Network Operators' Group" <nanog@nanog.org>
Sent: Sunday, September 27, 2020 1:22:51 PM
Subject: Re: Gaming Consoles and IPv4

I understand that. But there’s a host of reasons why that night not work - two devices trying to use UPNP behind the same PAT device, an apartment complex or hotel WiFi system, etc. 

On Sep 27, 2020, at 2:17 PM, Darin Steffl <darin.steffl@mnwifi.com> wrote:


This isn't rocket science.

Give each customer their own ipv4 IP address and turn on upnp, then they will have open NAT to play their game and host. 

On Sun, Sep 27, 2020, 12:50 PM Matt Hoppes <mattlists@rivervalleyinternet.net> wrote:
I know the solution is always “IPv6”, but I’m curious if anyone here knows why gaming consoles are so stupid when it comes to IPv4? 

We have VoIP and video systems that work fine through multiple layers of PAT and NAT. Why do we still have gaming consoles, in 2020, that can’t find their way through a PAT system with STUN or other methods?

It seems like this should be a simple solution, why are we still opening ports or having systems that don’t work?