Compare Analyses
Select two analyses of isc.org to compare
Click two rows to select them for comparison, then press Compare.
We use two cookies, both essential:
_csrf— Prevents cross-site request forgery. Required for form submissions. Security-only._dns_session— Only exists if you choose to sign in. No account required to use DNS Tool.
We log your IP address for two reasons: rate limiting (so nobody abuses the service) and security (identifying malicious actors and complying with legal obligations). We check source geography for analysis accuracy — DNS responses vary by region, and knowing which resolver answered from where makes the science better.
No tracking cookies. No analytics cookies. No ad networks. No data brokers. Our code is open-core — the application framework is publicly available under BUSL-1.1 with timed Apache-2.0 conversion. Verify it yourself.
If you create an account and want out, account deletion removes your login and scan history. Public domain analyses remain available because they contain only public DNS records, already hashed. Full details: Privacy Pledge.