[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: A mail relay server for Debian Members is live



On Aug 15, Ansgar <ansgar@43-1.org> wrote:

> To not look like forged mail, the "From" header field (not the
> envelope) has to be validated with either DKIM or SPF.  disroot.org
> says this is supposed to be the case for mail from their domain:
Not exactly. DMARC validation requires that at least one of DKIM or SPF 
is aligned.

DKIM validates the 822.From header, while SPF validates the 821.From 
envelope sender.

Forwarding emails does not break DKIM signatures, as long as the signed 
headers are not modified (and they are not supposed to be, so usually it 
is fine).
Forwarding emails does break SPF, and this is what SRS fixes (by 
changing the sender domain, so this does not help with DMARC).

Mailing lists always break SPF and they may or may not break DKIM 
depending if they change e.g. the message body or the Subject header.
The BTS does both, so after years it is still incompatible with DMARC 
validation (OTOH, domains which are not phishing targets should not 
enable DMARC. But we cannot fix other people's systems...).

-- 
ciao,
Marco

Attachment: signature.asc
Description: PGP signature


Reply to: