What domain blocklists (DBLs/RHSBLs) should I monitor?
Domain blocklists (also called RHSBLs - Right-Hand Side Blocklists) focus on domain reputation rather than IP addresses. These catch you even when sending from clean IPs.
High-impact domain blocklists:
| List | Zone | Impact |
|---|---|---|
| Spamhaus DBL | dbl.spamhaus.org | Very High - industry standard |
| SURBL | multi.surbl.org | High - checks URLs in body |
| URIBL | multi.uribl.com | High - SpamAssassin integrated |
| ivmURI | Invaluement | Medium-High - catches sophisticated spam |
Medium/Low-impact domain lists:
| List | Zone | Notes |
|---|---|---|
| SEM URI | uribl.spameatingmonkey.net | URI checking |
| SEM FRESH | fresh.spameatingmonkey.net | Newly registered domains |
| Nordspam DBL | dbl.nordspam.com | Nordic region focus |
| SORBS RHSBL | rhsbl.sorbs.net | Domain reputation |
What domain blocklists check:
- From: address domain
- HELO/EHLO domain
- Reply-To domain
- All URLs in message body
- Domains in message headers
Why domain reputation matters:
- IPs can change; domains are persistent identifiers
- Shared IP senders are judged by their own domain
- Bad links torpedo messages regardless of sender reputation
Domain blocklists are watching your identity, not your location. Change your port of origin all you want - if your ship's name is on the wanted list, you'll be stopped at inspection.
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