🚫 Spamhaus ZEN
What Spamhaus ZEN actually checks, which sub-zone you are on, and how to get delisted from SBL, XBL or PBL.
ℹ️ About This Blocklist
ZEN bundles three Spamhaus zones into one query: SBL (known spammers), XBL (compromised machines), and PBL (ranges that should not be sending mail directly). It is the most widely consulted DNSBL on the internet.
What a Listing Means
The IP is flagged by at least one of the three zones. SBL means a known spam operation, XBL means a compromised or botnet host, PBL means a range the ISP has declared should not send mail directly.
🔢 DNSBL Return Codes
When listed, the DNSBL returns one of these 127.x.x.x addresses. The specific code indicates the reason for the listing.
| Return IP | Meaning |
|---|---|
| 127.0.0.2 | SBL: direct spam source |
| 127.0.0.3 | SBL CSS: snowshoe spam operation |
| 127.0.0.4 | XBL: compromised or infected host (CBL data) |
| 127.0.0.9 | SBL: Spamhaus DROP or EDROP listing |
| 127.0.0.10 | PBL: range declared non-mail by the ISP |
| 127.0.0.11 | PBL: range declared non-mail by Spamhaus |
✅ How to Request Delisting
Run the IP through the Spamhaus Blocklist Removal Center to see which sub-zone hit. SBL and XBL have self-serve removals. PBL removal goes through your ISP or the Spamhaus PBL form.
Request Removal from Spamhaus ZEN ↗📚 Official Documentation
🔍 Check Your IP or Domain Against Spamhaus ZEN
Run a live blacklist check against all 17 blocklists we monitor, including Spamhaus ZEN.