IP Reputation and Blocklist Check
Enter a sending IP address to see its reverse DNS name and whether the major DNS blocklists have it listed. Useful the moment your mail starts bouncing.
Blocklists are queried by reversing the address and asking DNS, exactly as a receiving mail server would.
How to use
- Find the sending IP in a bounce message or your mail server logs and paste it above.
- Press Check reputation. Each blocklist is queried in parallel and the reverse DNS name is fetched alongside.
- If you are listed, use the delisting page for that list, but fix the cause first or you will be relisted within days.
Frequently asked questions
- Which lists are checked?
- A spread of widely used zones including Spamhaus, SpamCop, Barracuda, SORBS and UCEPROTECT. Some operators rate-limit public resolvers, so an inconclusive answer is not the same as clean.
- Why does reverse DNS matter?
- Many receivers reject mail from an IP with no PTR record, or where the PTR name does not resolve back to the same address. It is one of the cheapest deliverability fixes.
- Are IPv6 addresses supported?
- Not yet. Most blocklists have limited IPv6 coverage, so this tool focuses on IPv4.