Reverse DNS Lookup
Resolve IPs to hostnames
Source Input
Processed Output
What is the Reverse DNS Lookup?
Reverse DNS maps an IP address back to a hostname via PTR records. Mail servers almost always require correct reverse DNS (matching HELO/EHLO) or their email lands in spam folders. This tool resolves PTR records live so you can verify mail server and VPS configurations.
Frequently Asked Questions (FAQ)
Q: Why does reverse DNS matter for email?
Receiving mail servers compare the sender's PTR record with its HELO greeting; mismatches are a major spam signal.
How to Use the Reverse DNS Lookup
- 1Paste your input into the editor above — or start from the preloaded example.
- 2Adjust any options, then click Run to process instantly in your browser.
- 3Review the output panel, then copy, download, or save it as a reusable snippet.