Re: The Reg does 240/4

[Owen DeLong via NANOG <nanog () nanog org>]

Mike, it’s true that Google used to be a lot less strict on IPv4 email than IPv6, but they want SPF and /or DKIM on 
everything now, so it’s mostly the same. There is less reputation data available for IPv6 and server reputation is a 
harder problem in IPv6, but reputation systems are becoming less relevant. 

YMMV, but if your mail server is properly configured for SPF and DKIM, you shouldn’t have any difference in SMTP 
experience with Google for either protocol. 

Owen


> On Feb 16, 2024, at 07:20, Mike Hammett <nanog () ics-il net> wrote:
>
> 
> "Does any IPv6 enabled ISP provide PTR records for mail servers?"
>
> I think people will conflate doing so at ISP-scale and doing so at residential hobbiyst scale (and everything in 
> between). One would expect differences in outcomes of attempting PTR records in DIA vs. broadband.
>
> "How does Google handle mail from an IPv6 server?"
>
> A few people have posted that it works for them, but unless it has changed recently, per conversations on the mailop 
> mailing list, Google does not treat IPv6 and IPv4 mail the same and that causes non-null issues.
>
>
>
> -----
> Mike Hammett
> Intelligent Computing Solutions
> http://www.ics-il.com
>
> Midwest-IX
> http://www.midwest-ix.com
>
> From: "Stephen Satchell" <list () satchell net>
> To: nanog () nanog org
> Sent: Wednesday, February 14, 2024 8:25:03 PM
> Subject: Re: The Reg does 240/4
>
> On 2/14/24 4:23 PM, Tom Samplonius wrote:
> > The best option is what is happening right now:  you can’t get new IPv4
> > addresses, so you have to either buy them, or use IPv6.  The free market
> >   is solving the problem right now.  Another solution isn’t needed.
>
> Really?  How many mail servers are up on IPv6?  How many legacy mail
> clients can handle IPv6?  How many MTA software packages can handle IPv6
> today "right out of the box" without specific configuration?
>
> Does any IPv6 enabled ISP provide PTR records for mail servers?
>
> How does Google handle mail from an IPv6 server?
>
> The Internet is not just the Web.