Instantly check if an IP address or domain is listed on major free DNS blacklists. Scan Spamhaus, Barracuda, SpamCop, SORBS, and more in seconds.
The IP & Domain Blacklist Checker queries major free DNSBLs (DNS-based blocklists) to see if an IP address or domain is listed for spam, malware, or abuse.
Use it to diagnose deliverability problems, check sender reputation, or verify whether your infrastructure is blocklisted.
Checks Spamhaus, Barracuda, SpamCop, SORBS, and other free DNSBL zones.
Auto-detects input type and resolves MX IPs for domain checks.
Per-zone status, response codes, and delisting links where available.
Composite score showing overall blacklist health at a glance.
Paste an IPv4/IPv6 address or domain name to check.
For domains, resolves A and MX records to find all IPs to check.
Looks up each IP/domain against configured blocklist zones in parallel.
See which zones list the target, with response codes and delisting URLs.
Not listed on any checked DNSBL zones, good sender reputation signal.
One or more blocklists list this IP or domain, expect deliverability impact.
Some zones timed out or returned ambiguous responses, retry or check manually.
0-100 based on listing count and zone weights.
Per-zone status with response code and detail message.
For domains, shows each MX host and its resolved IPs checked separately.
A records and MX records found for the queried domain.
Test the IPs your mail server or ESP actually uses, not just the domain.
Use delisting URLs in results to begin removal from each list.
Listings often indicate compromised accounts, open relays, or spam complaints.
Re-check after delisting to confirm removal and prevent re-listing.
A DNS-based blocklist that returns specific DNS responses when an IP or domain is listed for abuse.
Mail from a domain sends from its MX servers, those IPs affect deliverability.
No. Inbox placement also depends on content, engagement, and authentication.
It varies by zone, the tool interprets each zone's response codes automatically.
Weekly for production sending infrastructure, or immediately after deliverability issues.
SenderSignal monitors these signals continuously: 48 blacklists, SPF, DKIM, DMARC, TLS and more, with alerts in Slack, email and signed webhooks.