The main features of DansGuardian 2.4 are as follows:
- Significantly cheaper than IGear (one of the best commercial filters).
- Can block adverts by the use of an advert URL block list.
- Can filter text and HTML pages for obscene (sexual, racial, violent, etc) content.
- Uses an advanced phrase weighting system to reduce over or under blocking.
- Can filter sites using the PICS labeling system.
- Can filter according to MIME type and file extension.
- Can filter according to URLs including Regular Expression URLs.
- URL filtering is compatible with squidGuard black lists.
- The URL filtering is able to filter https requests.
- Can work in a 'whitelist' mode where all sites except those listed are blocked.
- Can block all IP based URLs.
- Is able to block sites when users try using the IP address of the site instead.
- Produces a log in a very human readable format.
- Optionally produces a log in CSV format for easy import into databases etc.
- Is able to log the username using either Ident or basic proxy authentication.
- It has the ability to switch off filtering for specified sites, parts of sites, browser IPs and usernames.
- Can block specified source IPs and usernames.
- Can block or limit web uploading (e.g. attachments in Hotmail).
- Has the ability to work in a stealth mode where it logs sites that would have been blocked, but does not block them. This allows you to monitor your users without them knowing.
- Uses a very intelligent algorithm to match phrases in web pages mixed in with HTML code and white space.
- Big5, Unicode and top-bit set characters can be used in search phrases.
- DansGuardian 2.4.0 is over 6 times faster than DansGuardian 1.x.x.
- URL filtering is significantly faster than squidGuard.
- The configuration lists use the same incredibly fast code that allows them all to be hundreds of thousands of entries long.
- 100% C++ and can compile on GCC 3.
- Can be made to re-read config files with a HUP signal.
- Works perfectly in conjunction with Squid and Oops. Also see this important information.
- Has no 3rd party library requirements (no nb++ as was used in version 1) so can be installed much easier and so is also provided as an RPM.
- Supports (adds) the squid X-Forwarded-For header line.
- Supports compressed (Content-Encoding gzip and deflate) HTML.
- Can be made to only listen on 1 IP.
