What is Reverse-DNS verification?
Confirming a bot is who it claims to be.
Reverse-DNS verification (forward-confirmed reverse DNS) checks that a bot claiming to be, say, GPTBot really is: look up the visitor IP’s hostname, confirm it belongs to the operator’s official domain, then resolve that hostname forward and confirm it matches. Both directions must agree.
Without it, anyone can spoof a user-agent and pollute your data or hide as a trusted AI bot. CiteTrack runs this automatically and flags failures as spoofed, full walkthrough in how to verify a bot is real.
Why — and when — does it matter?
Verification prevents any visitor from claiming a trusted crawler name in its user-agent and contaminating security decisions or analytics.
How it works
Read the request IP.
Perform a reverse DNS lookup.
Verify the hostname ends in an operator-approved domain.
Resolve the hostname forward.
Confirm the original IP is returned and cache the result safely.
Worked example
A request says Googlebot, but its PTR record resolves to an unrelated hosting domain. It fails before the forward check and is classified as spoofed.
How to track and report it
Reporting rule: State the engine, prompt set, market, time window and denominator. A number without scope cannot be reproduced or compared.
Practical playbook
- Read the request IP.
- Perform a reverse DNS lookup.
- Verify the hostname ends in an operator-approved domain.
- Resolve the hostname forward.
- Confirm the original IP is returned and cache the result safely.
Common mistakes
- Checking only the hostname suffix
- Skipping the forward lookup
- Treating temporary DNS failure as proven spoofing
Questions people ask
What is Reverse-DNS verification?
Confirming a bot is who it claims to be. Verification prevents any visitor from claiming a trusted crawler name in its user-agent and contaminating security decisions or analytics.
How does Reverse-DNS verification work?
Read the request IP. Perform a reverse DNS lookup. Verify the hostname ends in an operator-approved domain. Resolve the hostname forward. Confirm the original IP is returned and cache the result safely.
How do you measure Reverse-DNS verification?
Verified, failed and unresolved request counts. Cache age and lookup failure rate. Verification rate = verified claimed-bot requests ÷ claimed-bot requests checked × 100
What is a common mistake with Reverse-DNS verification?
Checking only the hostname suffix. The scope and methodology should be stated before interpreting the result.
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