Making DMARC work with some custom records

I simply LOVE THIS MIAB Product. It’s pure genius. Hats off to the Developers!!

I run about 4-5 email domains on my little MIAB box that I run in AWS on a Lightsail instance. It just works beautifully. I spent several weeks getting my static IP “trained” and had a successful argument with the Internet Overloads at Microsoft and forced them to whitelist my IP, and now I have basically perfect email deliver-ability for all the email domains I host on this box.

BUT… I did have some head scratching challenges with configuring DMARC how I wanted it as i use GlockApps (free edition) to consolidate my reporting. Therefore I needed a modified DMARC record for each domain.

I looked at this for two days and just could not figure out how to make my Custom DNS record supersede the default on. Recall the default DMARC Record the MIAB creates looks like this:

v=DMARC1; p=quarantine;

Well I wanted something like this:

v=DMARC1; p=reject; rua=blah blah blah; ruf=blah blah blah; adkim=s; aspf=s; fo=1; ri=86400;

And for 48 hours I could not make it work… scratched my head raw.

Then BINGO…Eureka Moment… MIAB DMARC record is VERY VERY fussy about spaces. SO I pasted my custom record in ensuring that I had a after the semi-colon all the way thru the record and BOOM! The External default DNS record gets superseded. The space it seems super fussy about is the one between “1; p=”

Give it a try and BINGO you have your custom DMARC record.

Once you add the properly formatted custom DMARC record, the External DMARC record will change from:

“|Recommended. Specifies that mail that does not originate from the box but claims to be from @mydom.com or which does not have a valid DKIM signature is suspect and should be quarantined by the recipient’s mail system.|”

to:

“|(Set by user.)|”

I hope this helps

Terry

2 Likes

I use it like this as well, and it works indeed. Good of you to document it here! :+1: