Help with DomainKey and how the DNS record(s) are setup

I have read the CM info on DomainKey/DKIM setup ( and t=100) and am trying to get my head around in general about how to best reduce my 3rd-party mail services being viewed spam.  This post is not specific to CM, but more general with the implementation of the DomainKey records on my DNS.

We have already established a TXT record on our DNS of "" with the parameters of "k=rsa; t=y; p=MHww..."

I read more DomainKey info at, and they explain:
++++ BEGIN QUOTE ++++
You can only setup one DomainKey policy record per domain - but you can setup multiple selector records. The selector record holds your public key. You can setup multiple selectors to be used on different servers if you like, or you can use one selector for all your outgoing email. You can also create a selector that only works for one specific email address. Here is an example selector record:

myselector._domainkey.yourdomain.tld TXT "k=rsa; p=AIGf ... AQAB"

++++END QUOTE ++++

When the Campaign Monitor DomainKey record was setup, it was "".  I assume but would like some independent verification that the "cm" part of that record is arbitrary, meaning it could just as well have been "xyz", and that it has no intrinsic, predefined, or functional meaning within the record.  It's simply an identifier which called "myselector" in their syntax format above.

The reason for this question is that I also use Survey Monkey for some specific small tasks, and I would like to setup a DomainKey for that as well, in order to reduce those 3rd-party mailings being viewed as spam.  I was going to set up a new TXT record as:  "" along with additional parameters.  Would that work and would it effectively reduce begin caught by filters?  (We've already included the domain of" in the SPF record.)

But I don't fully understand "public keys" and how they interact with the DNS record, and who & how they are used.  Any links to more references or some lay explanations would be useful.

Thanks for any thoughts!

Dave Dave, 8 years ago

Hey Chris,

Thanks for your question. First things first, can you confirm if Survey monkey is actually signing your emails with DomainKeys when they send them out? It's only worth adding a new record to your DNS if that's the case.

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