[153336] in North American Network Operators' Group
Re: Our first inbound email via IPv6 (was spam!)
daemon@ATHENA.MIT.EDU (Jeroen Massar)
Tue Jun 5 10:34:06 2012
Date: Tue, 05 Jun 2012 07:33:19 -0700
From: Jeroen Massar <jeroen@unfix.org>
To: Raymond Dijkxhoorn <raymond@prolocation.net>
In-Reply-To: <alpine.LFD.2.00.1206051626590.13070@noc.prolocation.net>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 2012-06-05 07:29, Raymond Dijkxhoorn wrote:
[..]
> ;; ANSWER SECTION:
> comcast.net. 358 IN MX 5 mx3.comcast.net.
> comcast.net. 358 IN MX 10 mx1.comcast.net.
> comcast.net. 358 IN MX 5 mx2.comcast.net.
>
> ;; ADDITIONAL SECTION:
> mx2.comcast.net. 6958 IN A 76.96.30.116
> mx3.comcast.net. 358 IN A 68.87.26.147
> mx1.comcast.net. 358 IN AAAA 2001:558:fe14:70::22
>
> You are now only accepting IPv6 if all IPv4 fails?
> Or will AAAA records for mx2 and mx3 added later?
Though it can work, it used to be a really bad idea as there where a
couple of SMTP systems (Communigate Pro being one of them I recall)
which just failed when not seeing an "A" on an MX, this as they did not
understand IPv6...
There is bound to be other systems that are broken like that that will
not failover to the secondary MX, as such, you might want to add an IPv4
address there too just in case.
Greets,
Jeroen
