Each rule element in the request filter defines a simple matching expression and the action to take if a match is found. You can define as many rules as needed. This provides a flexible "or" operation where any one rule can cause the request to be blocked.

• servervar: This is the name of a Server variable from the Request.ServerVar hash table. See: http://www.w3schools.com/asp/coll_servervariables.asp
• operator : Defines the operation that determines whether an actual match exists. Valid values: Regex, Equal, NotEqual
  
  • Regex:  Uses the regular expression specified in the value attribute to determine a match.
  • Equal:  Performs a search of the value list to determine if the value of the specified server variable is in the value list.
  • NotEqual:  Performs a search of the value list to determine if the value of the specified server variable does not exist in the value list.
• value      : Defines the value of the servervar that triggers the rule. For a regex rule, the value should be a regular expression that used as a matching expression.
  If this is not a regex operation, then value can be a semicolon delimited list of values. For example it could include a list of IP addresses that should be blocked.
• action     : Defines the action to take if a match occurs. Valid values: NotFound, Redirect, PermanentRedirect.
  
  • NotFound:  Returns a 404 status code and stops all further response processing.
  • Redirect:  Performs a standard redirect to the url specified in the location attribute.
  • PermanentRedirect:  Performs a permanent redirect (status code 301) to the url specified in the location attribute.
• location  : The url where the request will be redirected. This can be left blank for the 'NotFound' action.

Host administrators can enable and disable the Request Filter from the HostSettings screen.  This settings page also provides an editor for adding, updating and deleting rules 

It is important to note that it is possible to lock yourself out of the website if you misconfigure a rule.   For example if you intend to prevent an IP address from accessing the site, you might want to create a rule like the one below:

{rule servervar="REMOTE_ADDR" values="205.196.10.2" operator="Equal" action="Redirect" location="http://www.disney.com" />