NAME
    URILocalBL - blocklist URIs using local information (ISP names, address
    lists, and country codes)

SYNOPSIS
    This plugin creates some new rule test types, such as "uri_block_cc",
    "uri_block_cidr", and "uri_block_isp". These rules apply to the URIs
    found in the HTML portion of a message, i.e. <a href=...> markup.

      loadplugin    Mail::SpamAssassin::Plugin::URILocalBL

    Why local blocklisting? There are a few excellent, effective, and
    well-maintained DNSBL's out there. But they have several drawbacks:

    * blocklists can cover tens of thousands of entries, and you can't
      select which ones you use;

    * verifying that it's correctly configured can be non-trivial;

    * new blocklisting entries may take a while to be detected and entered,
      so it's not instantaneous.

    Sometimes all you want is a quick, easy, and very surgical blocklisting
    of a particular site or a particular ISP. This plugin is defined for
    that exact usage case.

RULE DEFINITIONS AND PRIVILEGED SETTINGS
    The format for defining a rule is as follows:

      uri_block_cc SYMBOLIC_TEST_NAME cc1 cc2 cc3 cc4 ..
      uri_block_cc SYMBOLIC_TEST_NAME !cc1 !cc2 ..

    or:

      uri_block_cont SYMBOLIC_TEST_NAME co1 co2 co3 co4 ..
      uri_block_cont SYMBOLIC_TEST_NAME !co1 !co2 ..

    or:

      uri_block_cidr SYMBOLIC_TEST_NAME a.a.a.a b.b.b.b/cc

    or:

      uri_block_isp SYMBOLIC_TEST_NAME "Data Rancid" McCarrier Phishers-r-Us

    Example rule for matching a URI in China:

      uri_block_cc TEST1 cn

    If you specify list of negations, such rule will match ANY country
    except the listed ones (Finland, Sweden):

      uri_block_cc TEST1 !fi !se

    Continents uri_block_cont works exactly the same as uri_block_cc.

    This would block the URL http://www.baidu.com/index.htm. Similarly, to
    match a Spam-haven netblock:

      uri_block_cidr TEST2 65.181.64.0/18

    would match a netblock where several phishing sites were recently
    hosted.

    And to block all CIDR blocks registered to an ISP, one might use:

      uri_block_isp TEST3 "Data Rancid" ColoCrossing

    Quote ISP names containing spaces.

    Lastly, if there's a country that you want to block but there's an
    explicit host you wish to exempt from that blocklist, you can use:

      uri_block_exclude TEST1 www.baidu.com

    if you wish to exempt URL's referring to this host. The same syntax is
    applicable to CIDR and ISP blocks as well.

DEPENDENCIES
    The Country-Code based filtering can use any Mail::SpamAssassin::GeoDB
    supported module like MaxMind::DB::Reader (GeoIP2) or Geo::IP. ISP based
    filtering might require a paid subscription database like GeoIPISP.