nanog mailing list archives

Re: why IPv6 isn't ready for prime time, SMTP edition


From: "John Levine" <johnl () iecc com>
Date: 25 Mar 2014 17:56:03 -0000

In article <5331C054.8040801 () 2mbit com> you write:
On 3/25/14, 11:23 AM, John Levine wrote:
Large mail providers all agree that v6 senders need to follow good
mail discipline, but are far from agreeing what that means.  It
certainly means proper rDNS, but does it mean SPF?  DKIM on all the
mail?  TLS on the connections?  At this point, I don't know and
neither does anyone else.  Fortunately we have at least another decade
of full IPv4 mail connectivity to figure it out.

So, what's everyone's feelings about a rather large provider who blocks 
IPv6 e-mail that has no RDNS, even though the sending domain has SPF 
records allowing the block, and proper DKIM set up?

*looks directly at Google*

I think this would be a good time to fix your mail server setup.
You're never going to get much v6 mail delivered without rDNS, because
receivers won't even look at your mail to see if it's authenticated.

CenturyLink is reasonably technically clued so it shouldn't be
impossible to get them to fix it.

R's,
John


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