RE: IPv4 flag day

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

As to the last part, that would be way simpler.

Take that up with the RIRs though……

But I view each service having its own external address as a benefit, especially from a security/monitoring 
perspective. That’s just really a non-issue either way though.

Then again, I also statically address a fair amount of systems, so they’re easy to remember, with ::3 and ::4 addresses 
for externally facing stuff, and encode things like network segment or site in the prefix side if I can.

From: Aaron C. de Bruyn <aaron () heyaaron com>
Sent: Friday, June 19, 2026 4:05 PM
To: North American Network Operators Group <nanog () lists nanog org>
Cc: Marco Moock <mm () dorfdsl de>; Gary Sparkes <gary () kisaracorporation com>
Subject: Re: IPv4 flag day

On Fri, Jun 19, 2026 at 12:50 PM Gary Sparkes via NANOG <nanog () lists nanog org<mailto:nanog () lists nanog org>> 
wrote:
> So in IPv6 I either have to renumber because I ditched some ISP for another...or I have to pay for my addressing 
> space and my ISPs have to support routing my address space, right?

Yes, exactly like you had to for IPv4.

No, I didn't.
In IPv4 I can use RFC 1918 internally in a structured way and NOT have to renumber if I switch ISPs.
I unfortunately have to use NAT, and my single public IP will change, and I probably have to update a few DNS records .

But the big huge promise of IPv6 was "everyone and their dog can have a block of addresses bigger than the current 
internet" and "there's no more NAT or private addresses".
NAT 1:1 doesn't help here.  Instead of having a single public IPv4 with port forwards for MX (25, 465, 993, 110, 
etc...) and maybe a few for SSHing to various boxes (22, 221, 222, 223, etc...)
I now have a block bigger than the internet on my WAN that has to be 1:1 mapped into my MX (which used to be .250) and 
the various SSH hosts (.1, .2, .3, etc...)...and I need to update external DNS for MX to point to isp:bloc:k::1 for 
mail and isp:bloc:k::7 for one SSH host, etc...

Seems like it would be *way* simpler to say "here's youre free PI /48 your business can use, go number your internal 
network how you want and to connect to the internet, you need to give your ISP(s) your /48 so they can route it".
...at least on the business side of adopting IPv6.  On the "back end" everyone's routing tables would probably explode.

-A
_______________________________________________
NANOG mailing list 
https://lists.nanog.org/archives/list/nanog () lists nanog org/message/SUOPOHMSFC7RYBFK7HSY3NJNWSZ2WU2J/