One question I see a lot is “How can I let 3rd party vendors send as our organization using DKIM?” It’s a lot easier than you think. The trick is in the selector. Per RFC 6376: To support multiple concurrent public keys per signing domain, thekey namespace is subdivided using “selectors”. Implementing this is pretty straight-forward, so let’s getContinue reading “Selectors: The Magic Sauce of DKIM”