HACKER Q&A
📣 foxylad

How to Stop Gmail Rate-Limiting


Gmail messages from one of our mail servers (190.92.179.88) suddenly started being rate-limited a week ago. This affects thousands of Google's customers, who are getting their booking confirmations over 24 hours late.

We comply with every part of Gmails bulk sender guidelines. Both servers are registered with Postmaster Tools and have 0.0% spam stats; both have PTR, SPF and DMARC records; all messages are DKIM signed; neither server is on any blacklists.

We've filled in the form referred to on Gmail's bulk sender guidelines page twice, with no response or effect, and are now faced with the common problem of transmitting meaningful information through the Google event horizon.

Is anyone else experiencing this? Has anyone solved this in the past? Any Googlers able to pull a few strings to help thousands of YOUR customers?

  👤 LinuxBender Accepted Answer ✓
How to Stop Gmail Rate-Limiting

I don't have a good answer for stopping it given what you have tried thus far, but one can reduce the impact by distributing the outbound SMTP to different SNAT's, CIDR blocks, data-centers or even AS Numbers depending on how complicated of a setup one is willing to support. Every SNAT of course needs FCrDNS and all the additional CIDR blocks would need to be included in your existing SPF but that should reduce the threshold in effect.

👤 solardev
Maybe do a test with Sendgrid or Mailjet to see if they have more success? Generally Gmail hates small email providers... and Google doesn't care about anyone but its advertisers.
👤 kazinator
Don't rely only on mail for booking confirmations?

You need an alternative way for users to get their confirmations, and any associated documents, simple as that.

Those materials can be provided in a self-serve download area.

👤 sethammons
Moar IPs. Spread your load over after warming up the new one.