GBUdb Truncate DNSBL
The GBUdb Truncate DNSBL is an automated IP blocklist that uses strict statistics to list IPs sending spam, scams, and viruses.
Updated on 17 Jun 2026: We updated this guide with clearer DNS lookup, delisting, and SMTP rejection guidance.
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Check if you are listed on GBUdb Truncate DNSBL
And 143 other blocklists.
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0Spam
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NoSolicitado
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abuse.ro
ALPHANET
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SpamRATS
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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 GBUdb Truncate DNSBL?
GBUdb Truncate DNSBL is an IPv4-based Domain Name System Blocklist (DNSBL) that identifies addresses exclusively associated with harmful email. It operates under the zone truncate.gbudb.net. It is designed to be RFC 5782 compliant, a standard for DNS-based blacklists.
The policy for this blacklist is strict. An IPv4 address is listed only when statistical data from the global GBUdb network shows that it sends spam, scams, viruses, or other malware. When a system queries this blocklist about a listed address, a return code of 127.0.0.2 confirms the listing. Because the criteria are strict, administrators often reject SMTP connections from IPs on this list without a high risk of blocking legitimate email.
- The listing and delisting process is fully automated, with no manual addition or removal of entries.
- The blacklist (or blocklist) targets IPv4 addresses that are statistically associated with malicious email, which reduces false positives.
- The service is provided as-is with no warranty, and support is available on an as-available basis.
Who runs GBUdb Truncate DNSBL?
The GBUdb project operates GBUdb Truncate DNSBL. GBUdb stands for "Good, Bad, Ugly database." It is a real-time, collaborative IP reputation system that gathers network statistics. The system uses those observations to identify the characteristics of content sent from IP addresses across the internet and to support Truncate DNSBL.
How to check a GBUdb Truncate listing
To check an IPv4 address, reverse the octets and query them under truncate.gbudb.net. For example, the reserved documentation address 203.0.113.25 would be queried as 25.113.0.203.truncate.gbudb.net.
DNS query exampleBASH
dig +short 25.113.0.203.truncate.gbudb.net A
A response of 127.0.0.2 means the address is listed. No A record response means the address is not listed in this DNSBL at the time of the query.
How do I get removed and delisted from GBUdb Truncate DNSBL?
Maintenance of the GBUdb Truncate DNSBL is completely automated. There are no provisions for manual removal or delisting requests. To be removed from this blacklist, the IPv4 address must stop sending mail that triggers the listing criteria, such as spam, scams, viruses, or malware. Removal often happens within a couple of days after the bad activity stops, although it can take longer when the IP has accumulated enough bad activity.
Before your IP can be automatically delisted, resolve the underlying cause of the problem. Investigate compromised user accounts, malware on your network, vulnerable web forms, open relays, or misconfigured applications that are sending unwanted mail. Fixing the root cause is the only durable way to stay off this and other blocklists.
What's the impact of being listed on GBUdb Truncate DNSBL?
Being listed on GBUdb Truncate DNSBL affects mail where a receiving system queries this DNSBL, and those receivers can reject the SMTP connection before accepting the message. Because the list is strict and automated, a listing is a strong signal that the sending IP has an active reputation or abuse problem. Treat it as a security incident: stop the bad traffic, review outbound logs, rotate compromised credentials, and confirm that only authorized systems send mail for your infrastructure.
