Regular expressions (REGEX) are powerful when used in the whitelist or blacklist. Regular expressions can be used to affect URLs containing a word, an IP address, part of a website, or an individual page on a website.
The format of regular expression statements is as follows:
Global wild cards: Entering a single asterisk (*) for the domain field will apply the subsequent expression to all domains. This wild-card method is provided as a way for users to create global expressions if necessary; however, it is important to note that this does incur a performance hit to the content filter. How severe this performance hit is depends on the total number of wild-card entries, the amount of traffic being pushed through the unit, and several other factors.
Matching sub-domains: Entering a sub-domain into the domain field — for example,
REGEX:accounts.youtube.com: — will not behave as expected, because contentfilter normalizes whatever is entered into this field into a 'top-level' domain name. In this case, the rule will apply to all
youtube.com domains, not just to
accounts.youtube.com. If you wish to apply a rule to a specific sub-domain, you will need to add the sub-domain to the expression field.
Match all URLs containing the word 'porn' on any site under any domain. (Please see the note about global wild-card entries above.)
Match all URLs on any site under the youtube.com domain. Simply adding youtube.com to the whitelist or blacklist has the same effect and requires less typing.
Match all URLs on any site under the youtube.com domain (same as previous example). This illustrates how contentfilter strips sub-domains. (Please see the note about matching sub-domains above.)
Match all URLs containing the word 'watch' on any site under the youtube.com domain.
Match all URLs on any HTTP site under the youtube.com domain.
Match all URLs on accounts.youtube.com.
Match all URLs with the Top Level Domain (TLD) of .edu
Match all URLs containing any combination of two words, x and y.
See http://www.regular-expressions.info/tutorial.html for an explanation of regular-expression syntax.