nanog mailing list archives

Re: comcast ipv6 PTR


From: Brielle Bruns <bruns () 2mbit com>
Date: Tue, 15 Oct 2013 10:37:32 -0600

On 10/15/13 10:20 AM, Bjørn Mork wrote:
In any case: All of you should expect legitimate, technical brilliant
users attempting to connect to your SMTP servers from IPv6 addresses
with no PTR records. This is not going to go away.  You are of course
free to refuse those connections, but personally I find a that rather
arrogant and pretty stupid decision.  The existence of a PTR record is
one of many factors to consider for your spam filter.  There never has
been any reason to make it an absolute requirement, and I am pretty sure
the score needs to be lowered with IPv6.

Or, as an alternative, actually use the SPF records that multiple big companies keep telling people to make sure they have.

I have my SPF records set to allow my IPv6 and IPv4 senders, why are they ignoring that and going just for an outright reject on inbound ipv6 mail?

At least, if its a defer, it has the chance to bounce over to one of my backup mail servers that doesn't have IPv6 (or in one case, has a mail server out of my directly assigned from ARIN /48 with working rdns).


--
Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org


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