Re: [Asrg] misconception in SPF

Paul Smith <paul@pscs.co.uk> Fri, 07 December 2012 19:40 UTC

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Date: Fri, 07 Dec 2012 19:33:58 +0000
From: Paul Smith <paul@pscs.co.uk>
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Subject: Re: [Asrg] misconception in SPF
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On 07/12/2012 17:16, SM wrote:
> Hi Paul,
> At 08:53 07-12-2012, Paul Smith wrote:
>> Yes, the MX is for receiving mail only, according to the SMTP 
>> standard, BUT if you work on the assumption that you have to be able 
>> to reply to the sender (which is a common
>
> Actually no, or else people would not be using noreply@example.
Do people really send messages with a return path of 'noreply@example'? 
Or, do you mean that people use a return path of 'noreply@<their own 
domain>'?

With the former, I'd expect a large number of those messages to be 
blocked/discarded (it's common to do call back verification, or just 
simply check that the sender domain exists). I'd only expect that to be 
done by people who don't really understand what's going on. I know we 
have to deal with quite a few cases where our customers have errors or 
missing messages, which turn out to be because they've misspelled the 
domain part of their email address, and their mail is being 
blocked/discarded because the return address is invalid.



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