Check any IP or domain against 12+ public DNSBLs in seconds.
Paste an IPv4 address or sending domain — we check it against Spamhaus, Barracuda, SpamCop, the SORBS family, UCEPROTECT, Mailspike, CBL, GBUdb, and PSBL in parallel. Listings tell you why mailbox providers are downranking your mail.
The lists are not equal, and this is the part that causes unnecessary panic. A Spamhaus ZEN listing is the one that actually stops mail; a hit on an obscure regional list is usually informational.
A clean check now does not guarantee a clean check tomorrow — listings arrive silently and you normally find out from a customer. The Blacklist Monitoring add-on re-checks 90+ lists daily on every IP and domain you onboard.
Spamhaus ZEN, Barracuda BRBL, SpamCop SCBL, SORBS (dnsbl + spam), CBL/Abuseat, PSBL, UCEPROTECT (L1/L2/L3), Mailspike, GBUdb Truncate. Twelve lists in total, covering ~95% of what mailbox providers actually use.
L2 lists /24 networks — your specific IP isn't individually flagged, but a neighbour on the same /24 is. UCEPROTECT is the only major list that does network-level listings, and most mailbox providers don't consult L2 / L3 directly. Less urgent than a SBL hit.
Each list publishes its own delisting process. Spamhaus has a self-service portal for ZEN; Barracuda has a delisting form; SpamCop expects the issue (compromise / list hygiene) to be resolved before the listing auto-expires. Links are on each list's site.
Possible — not every mailbox provider checks every list. Major providers check Spamhaus heavily and SpamCop / Barracuda moderately; small/regional lists are usually consulted by smaller mail servers only.
Not via this tool — DNSBL lookups are per-IP. The Blacklist Monitoring add-on inside SieveGuard supports CIDR-range monitoring for tenants who manage IP allocations.
SieveGuard's Blacklist Monitoring add-on runs this check daily on every sending IP and domain you onboard, against 90+ lists, with alerts the moment a new listing appears. Catch drift in hours, not weeks.