Deep URL Analysis

When this option is enabled, DansGuardian looks for URLs inside other URLs, and checks the inside URLs against bannedsitelist (and exceptionsitelist) and bannedurllist (and exceptionurllist). This is especially useful to block images originating from banned sites from appearing in Google Images search results, as the original URLs are embedded in the thumbnail GET requests.

The usefulness of this option for limiting use of anonymous proxies is less clear.

This option does not even try to identify "obfuscated" URLs, such as those treated with hexadecimal encoding, base64 encoding, or even rot13 encoding. Such encodings of URLs, typically performed with Javascript, are quite common.

Note there are also legitimate reasons for having a URL inside another URL, for example to more securely, accurately, and easily convey "referrer" information to service websites. If problems are tracked to this option, consider experimenting with just turning it off.


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