Plain-language guides to email authentication, TLS, reverse DNS, and content grading.https://emailhealthpro.com/en-ushttps://emailhealthpro.com/learn/dkim/https://emailhealthpro.com/learn/dkim/DKIM signs every message you send with a private key, and publishes the public key in DNS so receivers can verify the signature. Here's how it works and how to set it up.Mon, 25 May 2026 00:00:00 GMTAuthenticationdkimdkim signaturedkim selectordkim dnsdomainkeys identified mailhttps://emailhealthpro.com/learn/dmarc/https://emailhealthpro.com/learn/dmarc/DMARC tells receivers what to do when a message claims to be from you but fails authentication. Here's how to read a DMARC record, pick the right policy, and read the reports.Mon, 25 May 2026 00:00:00 GMTAuthenticationdmarcdmarc policydmarc reportsdmarc rejectdmarc quarantinehttps://emailhealthpro.com/learn/spf-record/https://emailhealthpro.com/learn/spf-record/SPF is the first authentication check most mailbox providers run. Here's what an SPF record is, how to write one for your domain, and the gotchas that quietly break it.Mon, 25 May 2026 00:00:00 GMTAuthenticationspf recordsender policy frameworkspf dnsspf examplespf softfail vs fail