Email forwarding is a common practice in outbound sales. However, simple forwarding breaks SPF validation. When our server receives a message from `prospect@target.com` and forwards it to your `main@mycompany.com` inbox, the receiving server checks our server's IP against `target.com`'s SPF records. This check fails, triggering spam filters.
Cold Mail Server resolves this natively using Sender Rewriting Scheme (SRS). Our system rewrites the envelope sender address (the Return-Path) to point to our authorized domain, preserving SPF validation checks.
Simultaneously, we maintain DKIM signature headers, ensuring your inbound reply flows preserve validation compliance and land in your target CRM inbox.
A recipient replies to your campaign mailbox. Our server captures the incoming message.
Our SRS logic translates the envelope sender to point back to our authorized forwarding hosts.
We wrap the original headers while applying aligned SPF/DKIM keys to verify source integrity.
The translated mail lands in your main HubSpot/Slack/Gmail destination with validation intact.
| Feature Capability | Starter Tier | Scale Tier | Agency Tier |
|---|---|---|---|
| Sender Rewriting Scheme (SRS) | Automatic | Automatic | Automatic |
| Custom Target Rules | Up to 5 / domain | Unlimited | Unlimited |
| Forwarding Webhooks | No | Yes (Standard JSON) | Yes (Secure HMAC) |
| Catch-All Address Routing | Yes | Yes | Yes |
SPF defines which IPs are allowed to send mail on behalf of a domain. Simple forwarding doesn't change the Return-Path. When your inbox receives the forwarded mail, it sees our server IP sending as `prospect.com`, failing validation.
SRS (Sender Rewriting Scheme) rewrites the Return-Path to use our authenticated forwarding domain. This allows your final destination server to pass SPF validation checks cleanly.
Yes. Using SRS, the forwarded emails land cleanly in your CRM's inbound logging boxes. You can also configure Webhooks on the Scale/Agency plans.
No. You can configure forwarding patterns alongside your existing domain setup without changing your main MX records.
Run outbound campaigns without changing how your CRM collects responses.