The Spamhaus Project · IP addresses (individual IPs and IP ranges/netblocks). Not a domain list — Spamhaus lists domains separately on the DBL — though SBL data can indirectly affect domains whose authoritative nameservers sit on listed IPs.
Spamhaus SBL (Spamhaus Block List)
The SBL is a manually curated, real-time database of IP addresses that Spamhaus's investigators have identified as sources or supporters of spam — known spammers, spam gangs, spam operations, and spam-support services. It is one of the most widely deployed DNSBLs in the world (queried as sbl.spamhaus.org and bundled into the ZEN combined zone). It is evidence-based and human-reviewed rather than automatic, so a listing reflects a deliberate determination by Spamhaus, and it can be aggressive: persistent abusers can trigger "escalation" listings that block entire netblocks, not just a single IP.
Why you get listed
- The IP sent spam or hosted/supported a spam operation that Spamhaus investigators documented
- Snowshoe spamming — spreading spam thinly across many IPs/domains to evade volume-based filters
- Bulletproof or malicious hosting, botnet command-and-control, malware or ransomware distribution, or phishing tied to the IP
- Hosting spam-support infrastructure (e.g. spammer DNS, payment or redirect sites)
- Escalation: an ISP/host repeatedly tolerating abuse can get a wider range (or whole network) listed as a persistent-threat block
Impact
SBL is consumed by ISPs, enterprise mail servers, and most major spam-filtering platforms, usually via the ZEN zone. A listing means receiving servers reject or quarantine mail from the listed IP, so it can block delivery across a large share of the internet at once — not just at one mailbox provider. For anyone running their own sending IP it is one of the most damaging lists to be on. Note SBL targets sending-IP reputation specifically; it is distinct from PBL (which simply marks IPs that shouldn't be sending mail directly at all).
How to delist from Spamhaus SBL (Spamhaus Block List)
- Look up the offending IP at check.spamhaus.org to open its SBL listing and read exactly why it was listed and what evidence Spamhaus cites
- Actually fix the root cause first — stop the spam, close the open relay/compromised account, remove malware, secure the form/server. Spamhaus will NOT delist while the abuse is still observable
- Identify who controls the IP. Only the ISP / network owner / hosting provider responsible for the IP can request SBL removal — an end user or sysadmin generally cannot self-remove a manual SBL listing and must ask their ISP's abuse/security desk to submit it
- Have that responsible party use the 'contact the SBL Team' link at the bottom of the specific SBL listing page (reached via check.spamhaus.org) to submit a removal request with documentation of how the issue was remediated
- Wait for Spamhaus's human review; once the team confirms the abuse has ended, the listing is removed (the SBL zone rebuilds every ~5 minutes). Never pay anyone to 'expedite' — removal is always free
- CSS exception: if the listing is actually a CSS (Combined Spam Sources) entry rather than a manual SBL listing, it has its own self-service removal flow on check.spamhaus.org rather than going through the SBL team
Good to know
- Manual SBL listings are NOT self-service — only the ISP/network owner in control of the IP can request removal, and only after the abuse is genuinely fixed; Spamhaus refuses removal while spam is still active. General users must route the request through their ISP's abuse desk.
- Don't confuse SBL with related Spamhaus zones: CSS/SBLCSS (automated, published in the SBL/ZEN zone at return code 127.0.0.3) has self-service delisting at check.spamhaus.org and CSS entries auto-expire roughly 3 days after the last detected spam if the problem stops; PBL is a POLICY list (IPs that shouldn't send mail directly, e.g. dynamic/residential ranges) removed via a separate self-service PBL process — different from a real SBL spam listing.
- Removal is always 100% free; any third party claiming to remove or expedite a Spamhaus listing for a fee is a scam, and no consultant can influence Spamhaus's queue. The old 'Blocklist Removal Center' was retired and replaced by the IP & Domain Reputation Checker at check.spamhaus.org, which now houses the integrated delisting/ticketing flow.
Stay off the lists in the first place.
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