Re: [Bug-mailfromd] dmarc best practice

["Sergey Poznyakoff" <gray@xxxxxxxxxx>]

> My spammers are perfectly able to configure spf and other dns
> records. They are even doing this dynamically, just before they start
> spamming.

Sorry, you don't seem to have understood the idea.  They can tweak with
*their* DNS records to the best of their liking, but they cannot change
*mine* or *yours*.  So, if your server receives an email that claims to
be from gnu.org.ua, it will do a lookup for _dmark.gnu.org.ua, and that
record can be set up or changed only by someone who owns that particular
domain (unless his creds has been stolen, in which case he is done
for. anyway).

Regards,
Sergey