MikeL's FreeBSD howto - DMARC/SPF

[20221227]
Changes made to DNS:
For SPF:
In master file for domain, add $INCLUDE generic_spf.inc
In generic_spf.inc add:
    @ IN TXT "v=spf1 ip4:[your mail server ip/netmask] ip4:[your seconday mx server ip/netmask] mx:[your doamin] -all"
    mail IN TXT "v=spf1 ip4:[your mail server ip/netmask] ip4:[your seconday mx server ip/netmask] mx:[your domain] -all"
Using this method, you can use the same include file exactly as shown in the master file, for any/all other domains you may have hosted on this box.

For DMARC:
Just like above SPF, in master domain file, add $INCLUDE generic_dmarc.inc
In generic_dmarc.inc add:
    _dmarc IN TXT "v=DMARC1; p=quarantine; rua=mailto:[your email @ yourdomain]; ruf=mailto:[your email @ yourdomain]; adkim=r; aspf=r; rf=afrf"
    _dmarc.mail IN TXT "v=DMARC1; p=quarantine; rua=mailto:[your email @ yourdomain]; ruf=mailto:[your email @ yourdomain]; adkim=r; aspf=r; rf=afrf"
It's recommended that you have a specific email address for the dmarc mailto.


20191216 - Time for DMARC.

Note: I made SPF work a long time ago, and am not going to go into it now. Perhaps some time when I'm working on it again I'll document what I have...

Looking into DMARC, it's a bit daunting. Everyone says it's easy, but I'm not really finding exactly what I need for my DNS records. The one start I am finding is to add:
TXT "v=DMARC1; p-none; pct=100; rua=mailto:dmarc-reports@domain".
I've added this, of course changed my serial number and restarted named.
Evidently I'll now get weekly summary emails which will help me figure out what further I need to do. Good enough, hopefully the reports will start coming in and will remind me to get back to this.


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