What is Relay and how does it protect your inbox?
Relay is Cleanbox inbound mail protection. Unlike aliases which create new addresses, Relay protects your existing email addresses by filtering incoming mail before it reaches your mail server.
How Relay works
- Point your domain MX records to Cleanbox
- All incoming email arrives at Cleanbox first
- Each message is filtered: spam scoring, IP blacklist checks, contact states, filters
- Clean messages are forwarded to your actual mail server
- Spam and threats are blocked before reaching your inbox
Your existing email addresses keep working. The only difference is that Cleanbox sits in front as a protective gateway.
Relay vs. Aliases
| Aliases | Relay | |
|---|---|---|
| Creates | New email addresses | Protects existing addresses |
| Mail server | Not needed (Cleanbox delivers via IMAP) | Required (Cleanbox forwards to your server) |
| Outbound | Not supported (receive-only) | Unchanged — you send from your server |
| SPF/DKIM/DMARC | Managed by Cleanbox | Untouched — stays on your server |
What Relay filters
IP blacklist verification
Every sender IP is checked against DNSBL providers (Spamhaus, Barracuda, SpamCop) in real time. Blacklisted IPs are rejected at the connection level.
Spam scoring
Messages that pass the IP check are analyzed with the same spam engine as aliases, with per-address customizable thresholds.
Contact states and filters
Your contact states (whitelisted, blocked, muted) and filter rules apply to relay-protected addresses too.
Zero outbound changes
Relay only touches inbound mail. Your SPF, DKIM, DMARC records and sending reputation remain completely untouched.
Availability
- Advanced — Up to 20 relay accounts per domain
- Enterprise — Up to 100 relay accounts per domain
