🚫 RBL & Domain Blocklist Directory

Real-time Blocklists (RBLs) and Domain Block Lists (DBLs) are DNS-based databases used by mail servers to identify known spam sources. The TamingDNS Blacklist Checker queries all 17 blocklists listed here. Each entry below includes the listing criteria, return codes, and step-by-step delisting instructions.

How Blocklist Lookups Work

For IP lookups, the sending IP is reversed and prepended to the DNSBL hostname. For example, to check if 203.0.113.5 is on Spamhaus ZEN, a DNS A query is made for 5.113.0.203.zen.spamhaus.org. If an A record is returned, the IP is listed. The specific 127.x.x.x return value indicates which sub-list triggered the listing.

Domain blocklists (DBLs) work similarly but use the domain name directly: example.com.dbl.spamhaus.org.

🌐 IP-Based Blocklists (12)

Queried against the sending IP address of each mail server.

Spamhaus ZEN
zen.spamhaus.org
Composite zone combining the SBL (Spamhaus Block List), XBL (Exploits Block List…
Barracuda
b.barracudacentral.org
IP reputation list maintained by Barracuda Networks, used by Barracuda Email Sec…
SpamCop
bl.spamcop.net
User-reported spam blocklist operated by Cisco Talos. Listings are based on dire…
PSBL
psbl.surriel.com
The Passive Spam Block List (PSBL) is a conservative blocklist that lists IPs wh…
UCEPROTECT L1
dnsbl-1.uceprotect.net
UCEPROTECT Level 1 lists individual IPs that have sent spam. It's the most speci…
UCEPROTECT L2
dnsbl-2.uceprotect.net
UCEPROTECT Level 2 lists entire IP ranges (typically /24 subnets) that contain t…
WPBL
db.wpbl.info
The Weighted Private Block List (WPBL) is a collaborative blocklist based on wei…
CBL Abuseat
cbl.abuseat.org
The Composite Blocking List (CBL) lists IPs that have exhibited characteristics …
Spamhaus PBL
pbl.spamhaus.org
The Spamhaus Policy Block List (PBL) lists IP ranges that should not send email …
GBUDB
truncate.gbudb.net
The Good/Bad/Ugly Database (GBUDB) assigns reputation scores to IP addresses bas…
S5H
all.s5h.net
The s5h.net DNSBL is a small, manually curated blocklist maintained by a securit…
SPFBL
dnsbl.spfbl.net
SPFBL is a Brazilian-origin DNSBL that combines IP reputation, SPF validation, a…

🔗 Domain-Based Blocklists (5)

Queried against the domain name. Checks domain reputation regardless of sending IP.

Spamhaus DBL
dbl.spamhaus.org
The Spamhaus Domain Block List (DBL) lists domains that appear in spam messages.…
SURBL Multi
multi.surbl.org
SURBL (Spam URI Realtime Blocklist) lists domains that appear as links in spam m…
URIBL Black
black.uribl.com
The URIBL Black list contains domains that have appeared in unsolicited email. I…
Abuseat DBL
dbl.abuseat.org
The abuseat.org Domain Block List lists domains associated with spam and phishin…
NordSpam DBL
dbl.nordspam.com
The NordSpam Domain Block List is a domain reputation list focused on domains as…

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Run a live check against all 17 blocklists simultaneously.

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