On Wednesday 03 January 2018 at 02:39:54, Alex wrote:
> Hi,
>
> Is it possible to at least enforce that the message-ID has a valid domain?
If by "enforce" you mean "require" (in other words, you look at whatever
message-ID the incoming email has, and you decide that if it doesn't contain a
valid domain, then it is suspicious), then yes, you can.
However, this requirement is not stipulated by current RFCs, therefore you may
well be falsely marking legitimate email.
Only a check of the incoming mail you receive, to see whether "message ID
contains no valid domain" is a reliable indicator of spam, can tell you
whether it's a good idea to do this on your mail filtering.
The example quoted below is entirely RFC-conformant.
Antony.,
> Received: from thomas-krueger.local
> (221.208.196.104.bc.googleusercontent.com. [104.196.208.221])
> by smtp-relay.gmail.com with ESMTPS id
> r16sm1186220uai.7.2017.12.28.18.04.13
> for <amy.c...@example.com>
> (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
> Thu, 28 Dec 2017 18:04:14 -0800 (PST)
> X-Relaying-Domain: janda02.com
> Message-ID: <5b974eb73ed9c2d1b630f4b600191771@zfimvuyb.gwbba>
> From: "Apple Store" <mysendernuflwcix@zfimvuyb.gwbba>
> To: <amy.c...@example.com>
>
> On Tue, Jan 2, 2018 at 5:41 PM, @lbutlr <krem...@kreme.com> wrote:
> > On 2 Jan 2018, at 04:26, Rupert Gallagher r...@protonmail.com> wrote:
> >> Note taken. We still abide to the duties and recommendations, and expect
> >> well-behaved servers do the same, by identifying themselves. We
> >> cross-check, and if they lie, we block them.
> >
> > rejecting because they spoof a domain in the MID is one thing. Rejecting
> > an email because you misunderstood the RFC and don't see a valid domain
> > name is an entirely different thing.
--
"I estimate there's a world market for about five computers."
- Thomas J Watson, Chairman of IBM
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