Hello,
I have been running my own e-mail server for many years now, and have
been native IPv6 for... maybe 5 or 6 years?
I never have any problems, except for delivering to Comcast users. I
get bounces like this:
A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
xxx@comcast.net
SMTP error from remote mail server after initial connection:
host mx2.comcast.net [2001:558:fe21:2a::6]: 554 resimta-ch2-08v.sys.comcast.net comcast ESMTP server not available
yyy@comcast.net
SMTP error from remote mail server after initial connection:
host mx2.comcast.net [2001:558:fe21:2a::6]: 554 resimta-ch2-08v.sys.comcast.net comcast ESMTP server not available
Googling a bit I see this:
http://postmaster.comcast.net/smtp-error-codes.php
Comcast requires all sending mail server IP addresses have a
valid PTR record set up. This error results when the lookup failed.
NXDOMAIN response. One of the authoritative servers for the
relevant section of the in-addr.arpa DNS tree is saying that
there is no PTR record for the given IP address.
But I do have working reverse DNS:
$ ip addr | grep inet6
inet6 ::1/128 scope host
inet6 2a02:2770::21a:4aff:fea3:eeaa/64 scope global dynamic
inet6 fe80::21a:4aff:fea3:eeaa/64 scope link
$ host 2a02:2770::21a:4aff:fea3:eeaa
a.a.e.e.3.a.e.f.f.f.a.4.a.1.2.0.0.0.0.0.0.0.0.0.0.7.7.2.2.0.a.2.ip6.arpa domain name pointer c.time-travellers.nl.eu.org.
$ host c.time-travellers.nl.eu.org
c.time-travellers.nl.eu.org has address 46.19.37.141
c.time-travellers.nl.eu.org has IPv6 address 2a02:2770::21a:4aff:fea3:eeaa
The forward and reverse IPv6 DNS even match!
Are there any recommendations?
I hate to do AAAA filtering of Comcast's SMTP servers, but if that's
the only way to work around the brokenness, I guess I will so I can
talk to my family about their vacation photos... (Note that Comcast has
no issues sending me mail, so I get a lot of vacation photos.)
Cheers,
--
Shane
I have been running my own e-mail server for many years now, and have
been native IPv6 for... maybe 5 or 6 years?
I never have any problems, except for delivering to Comcast users. I
get bounces like this:
A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
xxx@comcast.net
SMTP error from remote mail server after initial connection:
host mx2.comcast.net [2001:558:fe21:2a::6]: 554 resimta-ch2-08v.sys.comcast.net comcast ESMTP server not available
yyy@comcast.net
SMTP error from remote mail server after initial connection:
host mx2.comcast.net [2001:558:fe21:2a::6]: 554 resimta-ch2-08v.sys.comcast.net comcast ESMTP server not available
Googling a bit I see this:
http://postmaster.comcast.net/smtp-error-codes.php
Comcast requires all sending mail server IP addresses have a
valid PTR record set up. This error results when the lookup failed.
NXDOMAIN response. One of the authoritative servers for the
relevant section of the in-addr.arpa DNS tree is saying that
there is no PTR record for the given IP address.
But I do have working reverse DNS:
$ ip addr | grep inet6
inet6 ::1/128 scope host
inet6 2a02:2770::21a:4aff:fea3:eeaa/64 scope global dynamic
inet6 fe80::21a:4aff:fea3:eeaa/64 scope link
$ host 2a02:2770::21a:4aff:fea3:eeaa
a.a.e.e.3.a.e.f.f.f.a.4.a.1.2.0.0.0.0.0.0.0.0.0.0.7.7.2.2.0.a.2.ip6.arpa domain name pointer c.time-travellers.nl.eu.org.
$ host c.time-travellers.nl.eu.org
c.time-travellers.nl.eu.org has address 46.19.37.141
c.time-travellers.nl.eu.org has IPv6 address 2a02:2770::21a:4aff:fea3:eeaa
The forward and reverse IPv6 DNS even match!
Are there any recommendations?
I hate to do AAAA filtering of Comcast's SMTP servers, but if that's
the only way to work around the brokenness, I guess I will so I can
talk to my family about their vacation photos... (Note that Comcast has
no issues sending me mail, so I get a lot of vacation photos.)
Cheers,
--
Shane