Do you support SRS (Sender Rewriting Scheme)?

How ImprovMX ensures SPF compatibility when forwarding emails.

Yes, ImprovMX implements a custom SRS solution to improve email forwarding deliverability.

What is SRS?

SRS (Sender Rewriting Scheme) is a mechanism designed to make email forwarding compatible with modern SPF (Sender Policy Framework) checks. Standard forwarding breaks SPF authentication because receiving servers see the forwarder's IP rather than the original sender's.

How Our SRS Works

Our implementation rewrites the envelope sender (Return-Path) to an address on a domain we control. This offers several benefits:

  • Ensures SPF checks pass at recipient mail servers
  • Reduces spam filtering and rejection risks
  • Maintains metadata about rewritten emails for bounce tracking
  • Allows tracing delivery errors back to original senders

Our custom SRS implementation helps ensure forwarded messages aren't flagged as spam or rejected entirely. It's one of the reasons your messages arrive where they're supposed to.

Learn More

For deeper technical understanding, see the SRS Wikipedia article.

Still have questions? Feel free to reach out to our support team!