Email Blacklist Checker

When you enter a domain name, we resolve its primary MX host (or fallback A record) to a public IPv4 address, reverse the four octets, and query each blocklist zone over DNS-over-HTTPS. An A-record response in the 127.0.0.x range indicates an active listing, while NXDOMAIN means the IP is not listed.

• Queries 4 public IPv4 DNSBL zones (SpamCop, Barracuda, PSBL, and UCEPROTECT Level 1) over Cloudflare DNS-over-HTTPS.
• If a DNSBL zone times out or returns a policy error code (such as 127.255.255.254), it is marked Unchecked rather than Not listed.
• Being Not listed on public DNSBLs does not mean Gmail, Yahoo, or Microsoft internal reputation systems trust the sender.
• Anonymous use is limited to 30 checks per hour. Inputs are not stored in the page URL or search index.

• IP reputation checker
• Email deliverability test
• MX lookup
• All free email tools