Re: [dmarc-ietf] Ticket #1 - SPF alignment

John Levine <johnl@taugh.com> Sat, 30 January 2021 21:23 UTC

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From: "John Levine" <johnl@taugh.com>
To: dmarc@ietf.org
Cc: fenton@bluepopcorn.net
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Archived-At: <https://mailarchive.ietf.org/arch/msg/dmarc/wdFAd8xT0tvwYWzT__BBXZUjFfA>
Subject: Re: [dmarc-ietf] Ticket #1 - SPF alignment
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In article <CF0B307A-C83A-4FF9-BC03-9DE28362DF3A@bluepopcorn.net> you write:
>The issue isn’t the existing use of HELO names, it’s how they could 
>be (mis-)used. The fact that a message sender can put anything there 
>makes HELO basically meaningless.

This is DMARC -- the HELO domain has to match the header From: and there
has to be an SPF record that validates it.

The most plausible case is that it's a bounce messsage

 From: MAILER-DAEMON@mta27.foo.bar.example.com

the MAIL FROM is null, HELO is mta27.foo.bar.example.com, and the SPF
record for mta27.foo.bar.com says that IP is OK.

I don't feel strongly about whether to use the HELO name but it doesn't break anything.

R's,
John