Re: [mlmmj] DMARC

Christof Thalhofer <[email protected]> Tue, 03 Mar 2020 00:36:18 +0000

Newsgroups	org.mlmmj.mlmmj
Message-ID	<[email protected]>

Am 02.03.20 um 12:13 schrieb Richard Torrens (lists):

> The member concerned is @casema.nl 
> 
> Other members postings nerver bounce for that reason. It's clear that
> casema.nl must have a stringent policy, but I cannot find out what is
> causing the problem.
> 
> Has anyone any hints or suggestions?

Please have a look at the nameserver TXT reponse for _dmarc.casema.nl:

> dig -t TXT  _dmarc.casema.nl 
> 
> ; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> -t TXT _dmarc.casema.nl
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47619
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
> 
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 512
> ;; QUESTION SECTION:
> ;_dmarc.casema.nl.		IN	TXT
> 
> ;; ANSWER SECTION:
> _dmarc.casema.nl.	3600	IN	TXT	"v=DMARC1; p=reject; rua=mailto:[email protected]; ruf=mailto:[email protected]; fo=1; adkim=s; aspf=s;"

They say, reject every mail that is supposed to come from casema.nl but
was sent from a server not being part of this domain.

The user [email protected] sent a mail to the mailinglist, the ML server
sends the mail to various recipients. The ML server is not part of
casema.nl.

The receiving mailservers ask the nameservers of casema.nl who is
allowed to send mails in the name of casema.nl. Because the mailserver
of the mailinglist is not, they reject the mail.


Alles Gute

Christof Thalhofer

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