Re: [Asrg] Fallback to MX

Ian Eiloart <> Fri, 12 February 2010 10:57 UTC

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Date: Fri, 12 Feb 2010 10:58:31 +0000
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Subject: Re: [Asrg] Fallback to MX
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--On 11 February 2010 15:39:55 +0000 John Levine <> wrote:

> There is no chance whatsoever that the RFC standards will change.

Ever? Even if it became common practice? I guess that the standards process 
isn't going to lead on this question.

> The idea of not accepting mail from domains with only AAAA records
> might be worth pursuing. I agree that despite what 5321 says, it seems
> pretty unlikely that such domains would ever send mail anyone wanted
> to receive.

Yes. Hey, I'm not even sure that we'd accept that email right now. I simply 
don't know if my MTA is IPv6 compatible in that way. I guess that I'd 
better find out...

Right, it seems that the MTA is capable, if compiled with IPv6 support, but 
since we've not got any IPv6 routing to the world on our network, our 
sender domain verification tests simply aren't going to work. That's nice. 
I've never had any complaints, and I will ensure when we do deploy IPv6, I 
don't permit email from domains that have AAAA but not A or MX records.

Ian Eiloart
IT Services, University of Sussex
01273-873148 x3148
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