Forum Discussion
Michael Wehking
Jun 11, 2019Copper Contributor
Third party email vendors and DKIM
Our group supports many agencies with in one tenant and with one sending domain. That said there are many outside vendors that send as "ourdomain.com". Is there a limit to the number of DKIM entries ...
Juan_CUMC
Jun 11, 2019Copper Contributor
Michael Wehking You can only have one DKIM per domain. If external vendors are spoofing your domain, DKIM will not work for you. You will need to use just SPF records.
Michael Wehking
Jun 11, 2019Copper Contributor
- andydavid1Jun 12, 2019Brass Contributor
Thats what SPF macros are for Michael Wehking .
But really you arent hostage to that limit. The RFCs allow multiple strings in the SPF record
Example:
- Michael WehkingJun 12, 2019Copper Contributor
andydavid1True but I don't believe SPF is going to check 40 to 50 addresses. I think 10 is the limit.
- Andy DavidJun 12, 2019MVP
Michael Wehking 10 DNS lookups. You mitigate that by not doing includes. Instead expand out all the allowed sending IPs and add those to the SPF record instead.