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Cornell University

Why Some Websites are Blocked

Why IT Security blocks some websites and what to do if a legitimate website is blocked

This article applies to: Security & Policy

Cornell University proactively blocks Internet sites that pose a security threat to the university or the Cornell community. Websites are deemed a security threat when they host malicious software or scripts, or are used to try to steal Cornell login information or passwords.

The university performs this classification both internally, in response to attacks targeting us, and through automated input from industry standard cybersecurity threat feeds.

Automated feeds bring together threat intelligence data from many sources. This ensures thoroughness and rapid blocks for dangerous websites, however, it can result in false positives, or delays when unblocking a website. If you believe your site falls into one of those categories, please contact the IT Security Office at

Cornell University does not block Internet sites unless our sources of threat information identify it as a risk to university computers, NetID credentials, or university data.


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