Appendix A. Filtering Rules

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You can specify individual settings to configure access to Internet resources. For that purpose, you can specify redefining rules.

In the current version of Dr.Web for UNIX Internet gateways, you can redefine the following parameters:

•BlockAdult—block access to websites with adult content.

•BlockViolence—block access to websites dedicated to violence: contain photos and videos of car accidents, plane crashes, natural disasters, etc.

•BlockWeapon—block access to websites dedicated to weapon: contain texts, photos, and videos of weapons (from cold steel to weapons of mass destruction) and information on manufacture of explosives.

•BlockGamble—block access to websites dedicated to gamble: to Internet casinos, gambling and bookmaking websites.

•BlockDrugs—block access to websites dedicated to drugs: contain information on drug production, distribution, and use.

•BlockObscenity—block access to websites with obscene language.

•BlockChats—block access to chats.

•BlockTerrorism—block access to websites dedicated to terrorism: contain detailed description of terroristic acts, manufacture of explosives, terrorist propaganda materials.

•BlockEmail—block access to websites that offer free email registration.

•BlockSocialNetwork—block access to social networks: dating websites, business social networking sites, corporate social networks, etc.

•BlockMalwareLinks—block access to known infection sources.

•BlockAll—block access to all websites.

Access rules are defined in the Rules section on the Filtering page; macros that are used in defined rules, should be specified in the Definitions section on this page.

To determine the actual status of accessibility to any website for a user, the following algorithm is used:

1.Dr.Web ICAPD checks whether the requested resource matches any of the pre-defined categories.

2.If the corresponding URL is found in such category (for example, in the Terrorism list), Dr.Web ICAPD defines the access mode for sites of this category. In Control Center, these settings are specified by corresponding flags (in the given example, Block terrorist websites) on the Filtering page.

3.The value is first searched in the Rules section according to the following algorithm:

•for all request variables, value of the if statement expression is calculated

•if true, the required parameter is searched in the configuration section

•if this parameter is found, its value is returned and the search completes

•if this parameter is not found or if the if statement is false, Dr.Web ICAPD goes to the next if statement.

4.If in the Rules section none of the rules is matching or does not contain the required parameter, the global parameter value is returned (or default value).

Search of the parameter value is performed until the first match; thus, the first found value is returned (from the configuration blocks of those if statements that have true expressions).

Внимание!

One Internet resource can be included into several categories of Internet resources as well as in a user-defined black list. In this case, access to this resource is blocked if at least one category is active. If it is necessary to allow access to such resource, deactivate all categories where it is included and exclude it from the user-defined black list.

However, to block access to other resources matching the deactivated black list categories, it is strongly recommended to include check of both URL of allowed recourse and client properties (such as IP address) into the condition of an allowing access rule.

 

Note that if an Internet resource is included in a user-defined black list, access to this resource cannot be allowed by a rule.