[GLLUG] British Gas DKIM failure?

[Henrik Morsing]

I'm now getting the same from the Land Registry:

Jan 27 18:05:24 emil postfix/smtpd[734113]: DA88621F91: client=d218-4.smtp-out.eu-west-2.amazonses.com[23.249.218.4]
Jan 27 18:05:24 emil postfix/cleanup[734121]: DA88621F91: message-id=<010b018d4c1902e5-14919a91-2793-4c5e-8d86-4091eaeb1175-000000 at eu-west-2.amazonses.com>
Jan 27 18:05:24 emil opendkim[768]: DA88621F91: d218-4.smtp-out.eu-west-2.amazonses.com [23.249.218.4] not internal
Jan 27 18:05:24 emil opendkim[768]: DA88621F91: not authenticated
Jan 27 18:05:25 emil opendkim[768]: DA88621F91: message has signatures from accounts.landregistry.gov.uk, amazonses.com
Jan 27 18:05:25 emil opendkim[768]: DA88621F91: s=s7vtg5zfwt6jcj77lxzbi3rmck6i6vrp d=accounts.landregistry.gov.uk a=rsa-sha256 SSL error:04091068:rsa routines:int_rsa_verify:bad signature
Jan 27 18:05:25 emil opendkim[768]: DA88621F91: bad signature data
Jan 27 18:05:25 emil opendmarc[1652567]: DA88621F91: accounts.landregistry.gov.uk fail
Jan 27 18:05:25 emil postfix/cleanup[734121]: DA88621F91: milter-reject: END-OF-MESSAGE from d218-4.smtp-out.eu-west-2.amazonses.com[23.249.218.4]: 5.7.1 rejected by DMARC policy for accounts.landregistry.gov.uk; from=<010b018d4c1902e5-14919a91-2793-4c5e-8d86-4091eaeb1175-000000 at eu-west-2.amazonses.com> to=<morsing at morsing.cc> proto=ESMTP helo=<d218-4.smtp-out.eu-west-2.amazonses.com>


I wish there was a test I could do to check what is actually wrong...

Regards,
Henrik Morsing


On Fri, Jan 12, 2024 at 03:48:17PM +0000, Henrik Morsing via GLLUG wrote:
>
>Good afternoon,
>
>Not dircetly Linux, sorry, but British Gas has spent the last year sending me letters saying they can't email me. When I look into it, their emails are rejected based on a bad DKIM signature.
>
>The problem is, not receiving the email, how can I find out what the problem is? mxtoolbox says their setup is fine, but that surely can't check the signature inside one of their emails.
>
>What is slightly odd is that DMARC policy is set to none, so shouldn't reject anything anyway.
>
>I can't say I'm a DKIM/DMARC expert, but this is what I see:
>
>Dec 22 12:37:12 emil opendkim[768]: 2F7612233E: s=mailjet d=britishgas.co.uk a=rsa-sha256 SSL error:04091068:rsa routines:int_rsa_verify:bad signature
>Dec 22 12:37:13 emil opendmarc[3858740]: 2F7612233E: britishgas.co.uk fail
>Dec 22 12:37:13 emil postfix/cleanup[3996586]: 2F7612233E: milter-reject: END-OF-MESSAGE from o94.p12.mailjet.com[87.253.237.94]: 5.7.1 rejected by DMARC policy for britishgas.co.uk; from=<296f63a1.CAAABPhWdncAAAAAAAAAAKg7aSYAAYCqUv4AAAAAABBDggBlhYBF at a1065858.bnc3.mailjet.com> to=<morsing at morsing.cc> proto=ESMTP helo=<o94.p12.mailjet.com>
>
>Not sure where to go from here though. Smells like their problem to me, but I don't want to tell them that without proof. Any hints?
>
>Regards,
>Henrik Morsing
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