Spamhaus Blocklist (SBL)
The Spamhaus Blocklist is an IP-based blocklist (blacklist) of sources involved in spam, helping administrators reduce harmful inbound email traffic.
Updated on 17 Jun 2026: We updated this guide with clearer SBL query details, delisting limits, informational listings, escalated listings, and prevention steps.
Summarize with
Check if you are listed on Spamhaus Blocklist (SBL)
And 143 other blocklists.
Spamhaus
0Spam
Cisco
NoSolicitado
URIBL
abuse.ro
ALPHANET
Anonmails
Ascams
BLOCKEDSERVERS
Calivent Networks
EFnet
JustSpam
Kempt.net
NordSpam
RV-SOFT Technology
Scientific Spam
Spamikaze
SpamRATS
SPFBL
Suomispam
System 5 Hosting
Team Cymru
Validity
www.blocklist.de Fail2Ban-Reporting Service
ZapBL
2stepback.dk
Fayntic Services
ORB UK
technoirc.org
TechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftWhat is Spamhaus Blocklist (SBL)?
The Spamhaus Blocklist (SBL) is a real-time, IP-based DNSBL of IP addresses and IP ranges that Spamhaus researchers identify as involved in spam or other network abuse. This blocklist (blacklist) includes sources tied to unsolicited bulk email, snowshoe spamming, spam-advertised hosting, bulletproof hosting, malicious content, or hijacked IP space.
According to Spamhaus's policy, IPs are added to the blacklist when they appear to be controlled by, used by, or made available for use by spammers or abusers. Spamhaus defines spam as "unsolicited bulk email" (UBE). It does not judge whether a message's content is legal; it focuses on whether the mail is unsolicited and bulk.
Email administrators use SBL data to reduce inbound spam and malicious email before it reaches users. The DNSBL zone for direct SBL lookups is sbl.spamhaus.org, while many mail servers use zen.spamhaus.org because ZEN combines SBL with other Spamhaus IP data for one query.
- At the initial SMTP connection, check the connecting IP address.
- During the pre-data phase of the SMTP transaction, check the HELO string and the "Mail From" domain.
- After message data is accepted, look up IP addresses that host resources found in the email headers, body, or URLs.
Who runs Spamhaus Blocklist (SBL)?
The Spamhaus Blocklist (SBL) is managed by Spamhaus Project, a non-profit organization founded by Steve Linford in London in 1998 and now based in Andorra. Spamhaus researches reputation data for IPs, domains, and ASNs used in spam, phishing, malware, ransomware, and related internet abuse.
Spamhaus began by tracking spam-sending IPs on a DNS Blocklist (DNSBL). Its current Open Source Intelligence (OSINT) research team and forensics specialists maintain SBL listings and related datasets. The team also works with network owners and abuse desks when listed infrastructure needs remediation.
How do I get delisted from Spamhaus Blocklist (SBL)?
The delisting process for SBL is handled directly with the network owner, ISP, ESP, or hosting company responsible for the listed IP space. When an IP is added to this blacklist, Spamhaus researchers send a notification to the company responsible for that IP range.
Because SBL listings usually involve infrastructure-level abuse, end users cannot remove their own IPs. If your IP is listed and you are not the network owner, contact your ISP or email service provider and ask them to investigate the SBL ticket.
The network owner must fix the abuse issue first, then use the instructions on the SBL listing page to request removal. Spamhaus says removals are its decision, there is no fee for SBL removal, and third parties cannot pay to speed up or force delisting.
SBL listing details can be checked by IP, IP range, or SBL ticket number through Spamhaus's reputation lookup page.
What's the impact of being listed on Spamhaus Blocklist (SBL)?
An SBL listing usually has a severe deliverability impact because many mail servers and security gateways use Spamhaus data in connection-time filtering. If a receiving system queries SBL or ZEN, listed IPs are often rejected before message content is accepted.
For senders, the result is blocked email, SMTP rejection notices, or mail routed to spam. The impact is worst for transactional email, customer support, billing, and marketing workflows because the listing affects the sending IP rather than a single campaign.
Spamhaus also has informational SBL listings. These indicate poor behavior and do not block mail by themselves, but they are an early warning that a full SBL listing can follow if the underlying issue is not fixed.
For networks that ignore listings or repeatedly make the same abusive infrastructure available, Spamhaus can escalate SBL listings to broader IP ranges, infrastructure IPs, or related networks.
How to avoid Spamhaus SBL listings
Avoiding an SBL listing depends on keeping sending infrastructure controlled, permission-based, and unavailable to abusive customers or compromised devices.
- Secure public signup and web forms with CAPTCHA or rate limiting so attackers cannot trigger mail bombing or unauthorized subscriptions.
- Use confirmed opt-in for marketing lists and remove addresses that bounce, complain, or show no engagement over time to reduce spam trap risk.
- Restrict outbound SMTP on port 25 so only approved mail servers send directly to the internet.
- Keep HELO and EHLO names, hostnames, and reverse DNS (PTR) records consistent for each sending IP.
- Enforce a clear acceptable use policy for customers and stop spam support services, bulletproof hosting, scraping tools, and malware infrastructure quickly.
- Review mail logs, complaint data, and bounce patterns so compromised accounts or scripts are found before abuse grows.
Other Spamhaus blocklists
Spamhaus Domain Blocklist (DBL)
Organization
Spamhaus
Zone
dbl.dq.spamhaus.net
Type
Domain
Impact
High
Delisting
Manual
Spamhaus Exploits Blocklist (XBL)
Organization
Spamhaus
Zone
xbl.dq.spamhaus.net
Type
IP
Impact
High
Delisting
Manual
Spamhaus Policy Blocklist (PBL)
Organization
Spamhaus
Zone
pbl.dq.spamhaus.net
Type
IP
Impact
High
Delisting
Manual
Spamhaus ZEN Blocklist
Organization
Spamhaus
Zone
zen.dq.spamhaus.net
Type
IP
Impact
High
Delisting
Manual
Spamhaus Zero Reputation Domain (ZRD)
Organization
Spamhaus
Zone
zrd.dq.spamhaus.net
Type
Domain
Impact
Medium
Delisting
Automatic
