NAME

       Mail::SpamAssassin::Plugin::ASN - SpamAssassin plugin to look up the Autonomous System Number (ASN) of
       the connecting IP address.

SYNOPSIS

        loadplugin Mail::SpamAssassin::Plugin::ASN

        asn_lookup asn.routeviews.org _ASN_ _ASNCIDR_

        asn_lookup_ipv6 origin6.asn.cymru.com _ASN_ _ASNCIDR_

        add_header all ASN _ASN_ _ASNCIDR_

        header TEST_AS1234 X-ASN =~ /^1234$/

DESCRIPTION

       This plugin uses DNS lookups to the services of an external DNS zone such as at
       "http://www.routeviews.org/" to do the actual work. Please make sure that your use of the plugin does not
       overload their infrastructure - this generally means that you should not use this plugin in a high-volume
       environment or that you should use a local mirror of the zone (see "ftp://ftp.routeviews.org/dnszones/").
       Other similar zones may also be used.

TEMPLATE TAGS

       This plugin allows you to create template tags containing the connecting IP's AS number and route info
       for that AS number.

       The default config will add a header field that looks like this:

        X-Spam-ASN: AS24940 213.239.192.0/18

       where "24940" is the ASN and "213.239.192.0/18" is the route announced by that ASN where the connecting
       IP address came from.  If the AS announces multiple networks (more/less specific), they will all be added
       to the "_ASNCIDR_" tag, separated by spaces, eg:

        X-Spam-ASN: AS1680 89.138.0.0/15 89.139.0.0/16

       Note that the literal "AS" before the ASN in the _ASN_ tag is configurable through the asn_prefix
       directive and may be set to an empty string.

CONFIGURATION

       The standard ruleset contains a configuration that will add a header field containing ASN data to scanned
       messages.  The bayes tokenizer will use the added header field for bayes calculations, and thus affect
       which BAYES_* rule will trigger for a particular message.

       Note that in most cases you should not score on the ASN data directly.  Bayes learning will probably
       trigger on the _ASNCIDR_ tag, but probably not very well on the _ASN_ tag alone.

SEE ALSO

       http://www.routeviews.org/ - all data regarding routing, ASNs, etc....

       http://issues.apache.org/SpamAssassin/show_bug.cgi?id=4770 - SpamAssassin Issue #4770 concerning this
       plugin

STATUS

       No in-depth analysis of the usefulness of bayes tokenization of ASN data has been performed.

ADMINISTRATOR SETTINGS

       asn_lookup asn-zone.example.com [ _ASNTAG_ _ASNCIDRTAG_ ]
           Use this to lookup the ASN info in the specified zone for the first external IPv4 address and add the
           AS number to the first specified tag and routing info to the second specified tag.

           If  no  tags  are specified the AS number will be added to the _ASN_ tag and the routing info will be
           added to the _ASNCIDR_ tag.  You must specify either none or both of the tag names.  Tag  names  must
           start and end with an underscore.

           If  two  or  more asn_lookups use the same set of template tags, the results of their lookups will be
           appended to each other in the template tag values in no particular order.  Duplicate results will  be
           omitted  when  combining  results.   In a similar fashion, you can also use the same template tag for
           both the AS number tag and the routing info tag.

           Examples:

             asn_lookup asn.routeviews.org

             asn_lookup asn.routeviews.org _ASN_ _ASNCIDR_
             asn_lookup myview.example.com _MYASN_ _MYASNCIDR_

             asn_lookup asn.routeviews.org _COMBINEDASN_ _COMBINEDASNCIDR_
             asn_lookup myview.example.com _COMBINEDASN_ _COMBINEDASNCIDR_

             asn_lookup in1tag.example.net _ASNDATA_ _ASNDATA_

       asn_lookup_ipv6 asn-zone6.example.com [_ASN_ _ASNCIDR_]
           Use specified zone for lookups of IPv6 addresses.  If zone supports both IPv4 and IPv6  queries,  use
           both asn_lookup and asn_lookup_ipv6 for the same zone.

       clear_asn_lookups
           Removes any previously declared asn_lookup entries from a list of queries.

       asn_prefix 'prefix_string'       (default: 'AS')
           The  string  specified in the argument is prepended to each ASN when storing it as a tag. This prefix
           is rather redundant, but its default value 'AS' is kept for backward compatibility with  versions  of
           SpamAssassin earlier than 3.4.0. A sensible setting is an empty string. The argument may be (but need
           not be) enclosed in single or double quotes for clarity.

perl v5.30.0                                       2023-03-24               Mail::SpamAssassin::Plugin::ASN(3pm)