0Spam Uniform Resource Locator Block List (URLBL)
The 0Spam URLBL is an IP-based blocklist (blacklist) containing IPs of domains found in spam emails.
Updated on 17 Jun 2026: We updated this guide with clearer 0Spam URLBL listing causes, delisting timing, and remediation steps.
Summarize with
Check if you are listed on 0Spam Uniform Resource Locator Block List (URLBL)
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 the 0Spam Uniform Resource Locator Block List (URLBL)?
The 0Spam Uniform Resource Locator Block List (URLBL) is an IP-based blacklist (blocklist) queried at dbl.0spam.org. It contains IP addresses tied to domains found inside emails that 0Spam identified as spam, so it is closer to a URL reputation list than a standard sender-IP DNSBL. 0Spam says this list should not be used as the only signal for spam filtering because legitimate messages can contain domains that also appear in spam.
The list was previously known as the FusionZero DNSBL, and older mail server configurations still use FusionZero references. If a mail server configuration still points to an old FusionZero zone, update it to the current 0Spam zone and test the result before applying it in production.
0Spam publishes reputation data; the receiving mail server decides whether to reject, quarantine, or accept a message. 0Spam also states that public DNS queries are free for private and commercial use up to 4,000 requests per 5 seconds, so production filters should account for that limit before adding the list to live filtering.
Who runs the 0Spam URLBL?
The 0Spam project runs the URLBL. 0Spam has operated since 2000 and supports ESPs, ISPs, MSPs, and system administrators with public DNS-based spam lists and paid network services. The project is supported by donations and service revenue.
In addition to the blacklist (or blocklist), 0Spam lists these related services:
- IP notification services notify verified network administrators when an IP they manage is about to be listed, with a 24-hour buffer before public listing.
- Network Asset Management is for IP owners who manage larger blocks and need bulk removals or abuse-notification workflows.
- Abuse notifications go to Regional Internet Registry (RIR) WHOIS abuse contacts for IPs found sending spam.
Why an IP appears on the 0Spam URLBL
A URLBL listing points to a domain found in spam, not necessarily to the outbound mail server that sent the message. 0Spam states that its reputation data comes from spam traps, repeated user spam reports, and machine-learning classification. The listed value can be an IP tied to a URL or domain that appeared in spam content.
This distinction matters during remediation. A sender can be affected because a message contains a listed domain, because a shared hosting IP contains compromised sites, or because a marketing campaign links to a domain that recently appeared in spam. 0Spam does not list individual email addresses.
- Check the exact domain and IP returned by the listing before changing mail-server policy.
- Review recent campaigns, shared-hosting domains, redirects, and URL shorteners for links that appeared in spam.
- Remove compromised pages, malware, or redirects before requesting delisting.
How to get removed from 0Spam URLBL
The removal process from this blacklist is free, but 0Spam limits requests to reduce automated abuse. First, check the suspected IP on 0Spam and stop the spam source. Then create an account on the 0Spam platform and submit a removal request. The public guidance says one IP can be removed every three hours.
0Spam says removal requests are automatically processed within 20 minutes. Requests flagged for manual review take up to 48 hours. For larger networks, 0Spam's Network Asset Management services support bulk removals and abuse notifications.
In rare repeated-abuse cases, an IP or network block gets a long-term listing. If that happens, stop all spam originating from the network for at least 60 days before applying for manual removal.
Before you request removal from this blocklist, complete these checks:
- Identify and resolve the root cause of the spam before submitting the request.
- Scan servers, websites, and user devices for malware, compromised scripts, and open relays.
- Secure compromised mailboxes, CMS accounts, API keys, and sending applications.
- Use confirmed or double opt-in for mailing lists and stop using purchased or scraped lists.
- Confirm that DNS and email authentication records are correct before sending again.
- If you operate free or trial email accounts, limit unverified sending and investigate shared IP abuse quickly.
- Confirm that commercial email practices comply with the CAN-SPAM Act.
What is the impact of a 0Spam URLBL listing?
The impact of a 0Spam URLBL listing is medium. It is not one of the largest blacklists (blocklists), but mail systems that query it can reject the message, quarantine it, or add spam-folder placement when the listed URL or domain appears in the message body. That can reduce delivery rate and engagement until the listed domain or hosting IP is cleaned up.
A listing also affects shared infrastructure. If the listed domain or hosting IP is shared with other customers, senders using clean practices can still see filtering problems until the provider removes abuse and completes delisting.
Other 0Spam blocklists
0Spam Block List (BL)
Organization
0Spam
Zone
bl.0spam.org
Type
IP
Impact
Medium
Delisting
Manual
0Spam Network Block List (NBL)
Organization
0Spam
Zone
nbl.0spam.org
Type
IP
Impact
Medium
Delisting
Manual
0Spam Realtime Block List (RBL)
Organization
0Spam
Zone
rbl.0spam.org
Type
IP
Impact
Medium
Delisting
Automatic
