Gmail with domain alias emails with DKIM/SPF/DMARC

posted

For years, I have been handling email with a gmail account, having my dns registrar forward all email to my domain to that account, and then adding sending aliases to the gmail account to send mail.

A few years ago gmail stopped doing the verification by just sending an email to the email you wanted to send from and started requiring SMTP, but I could just use an app password and smtp back to that gmail account and it seemed to be working fine.

Somewhere between 2025-09-12 and 2025-09-23 yahoo started rejecting the emails because of SPF/DKIM failures. Looking back, I had seen some warnings about this when I emailed my work outlook email, or looking at google's original message view.

It turns out I had SPF misalignment because Return-Path: $gmailUser@gmail.com and From: $domainEmail didn't match.

Google will mark this as SPF pass but DMARC fail, and in my brief testing it will usually deliver but sometimes get marked as spam?

The only way forward is to have someone else handle sending email properly.

I ended up choosing SMTP2GO because 1,000 emails/month on their free plain is fine for me.

Steps:

  1. create account
  2. do the verified senders domain verification setup
  3. add smtp user
  4. in gmail add a sending alias with the smtp user