RE: IPv4 flag day

[Gary Sparkes via NANOG <nanog () lists nanog org>]

I'd say it's not, as it's still a prevalent enough issue that IPv6 does increase reliability. 

And there's still a lot of NAT detection and workarounds.

Of course, centralized servers help a lot with avoiding the issue entirely, but not always. Modern Call of Duty has 
gotten better, for example, but still stumbles on NAT issues from time to time.

It's definitely not a solved problem if Sony's telling PS5 users to port forward, turn on UPnP, etc or DMZ (in the end 
user CPE usage of the term)  their consoles to make online gaming work better.

Some CPE is better than others, or has better out of box defaults, but even I've had to port forward for black ops (and 
just that COD game) to work before for matchmaking. (joining directly worked, just not lobby style matchmaking)

This is Sony's current troubleshooting advice for multiplayer game issues:
(And if you're having issues with voice chat, they dive straight into NAT troubleshooting and eventually tells you to 
forward additionally 49152-65535, and other games need even more)

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Try opening the following ports on your router:
TCP: 80, 443, 3478, 3479, 3480
UDP: 3478, 3479 

Please note, if you’re not sure what this means or don’t know how to open ports on your router, we recommend speaking 
to your ISP or router manufacturer before changing any settings.
Change your IP address from dynamic to static.
Most ISPs assign dynamic IP addresses to their customers. This means the IP address can change periodically. Asking 
your ISP to change your IP address from dynamic to static (one that always stays the same) can help achieve a more 
consistent, reliable connection with PlayStation services.
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-----Original Message-----
From: William Herrin <bill () herrin us> 
Sent: Friday, June 19, 2026 3:25 PM
To: North American Network Operators Group <nanog () lists nanog org>
Cc: Gary Sparkes <gary () kisaracorporation com>
Subject: Re: IPv4 flag day

On Fri, Jun 19, 2026 at 10:16 AM Gary Sparkes via NANOG <nanog () lists nanog org> wrote:
> Gaming is something that *HUGELY* benefits from IPv6/NAT elimination.

Peer to peer for gaming was yesterday's issue. Today, linking multiple players together is well solved and baked into 
the Steam library or whatever is specific to the game's platform. Meanwhile, anti-cheat measures require that the 
players be ignorant of each others' IP addresses so that they don't compete by lagging their competitors with a packet 
flood. Which used to happen a lot. There are still old titles out there being actively enjoyed where you have to poke a 
hole through the nat to play with each other, but as a broad concern NAT obstruction of online games is rapidly fading 
away. The game developers found themselves facing problems that couldn't be solved with peer to peer even if the 
network made it easy.

Regards,
Bill Herrin



--
For hire. https://bill.herrin.us/resume/
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