DKIM signing via CNAME
I would like to be able to do is simply to let our clients add a CNAME record to the [domain] DKIM record (mx._domainkey.[domain], and then, when sending we could specify the signing domain for the DKIM signature.
For example: to align the domains in the example above, I would just create a CNAME record at mx.domainkey.domain2.tld which point to mx.domainkey.domain1. Then, the DKIM signature would declare the signing domain as d=domain2 instead of d=domain1
The benefits of this are:
- We don't need to continually create and manage new domains in our account.
- The domains are aligned by signing the message using the same domain as the From header.