On 09/02/2026 14:19, Matthias via mailop wrote:
Hello,
some IONOS customer mail domains seem to have a default DMARC entry that points
to dmarc.ionos.de. This entry is invalid if i'm not fully mistaken:
$ dig +short txt dmarc.ionos.de
"v=DMARCv1; p=none;"
per https://datatracker.ietf.org/doc/html/rfc7489 the only allowed value for
the version field is DMARC1.
v: Version (plain-text; REQUIRED). Identifies the record retrieved
as a DMARC record. It MUST have the value of "DMARC1". The value
of this tag MUST match precisely; if it does not or it is absent,
the entire retrieved record MUST be ignored. It MUST be the first
tag in the list.
Anyone from IONOS here that could take a look at this? This causes issues on
some DMARC parsers which, in some cases, results in rejections - even though
the parsers should ignore the field, but this is a different story.
Best regards,
Matthias
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Hi Matthias
earlier in the same document, it mentions that records must start with
_dmarc.
6.1. DMARC Policy Record
Domain Owner DMARC preferences are stored as DNS TXT records in
subdomains named "_dmarc". For example, the Domain Owner of
"example.com" would post DMARC preferences in a TXT record at
"_dmarc.example.com".
If you follow that you get
dig +short txt _dmarc.ionos.de
"v=DMARC1;p=reject;sp=reject;pct=100;rua=mailto:[email protected],mailto:[email protected];ri=86400;aspf=r;adkim=r;fo=1";
I don't know what is the purpose of having a TXT record at
dmarc.ionos.de, but I don't think its existence or its value is relevant.
John
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