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.IX Title "Mail::SpamAssassin::Plugin::ASN 3pm"
.TH Mail::SpamAssassin::Plugin::ASN 3pm "2022-09-10" "perl v5.34.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.nh
.SH "NAME"
Mail::SpamAssassin::Plugin::ASN \- SpamAssassin plugin to look up the
Autonomous System Number (ASN) of the connecting IP address.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& loadplugin Mail::SpamAssassin::Plugin::ASN
\&
\& # Default / recommended settings
\& asn_use_geodb 1
\& asn_use_dns 1
\& asn_prefer_geodb 1
\&
\& # Do lookups and add tags / X\-Spam\-ASN header
\& asn_lookup asn.routeviews.org _ASN_ _ASNCIDR_
\& asn_lookup_ipv6 origin6.asn.cymru.com _ASN_ _ASNCIDR_
\& add_header all ASN _ASN_ _ASNCIDR_
\&
\& # Rules to test ASN or Organization
\& # NOTE: Do not use rules that check metadata X\-ASN header,
\& # only check_asn() eval function works correctly.
\& # Rule argument is full regexp to match.
\&
\& # ASN Number: GeoIP ASN or DNS
\& # Matched string includes asn_prefix if defined, and normally
\& # looks like "AS1234" (DNS) or "AS1234 Google LLC" (GeoIP)
\& header AS_1234 eval:check_asn(\*(Aq/^AS1234\eb/\*(Aq)
\&
\& # ASN Organisation: GeoIP ASN has, DNS lists might not have
\& # Note the second parameter which checks MYASN tag (default is ASN)
\& asn_lookup myview.example.com _MYASN_ _MYASNCIDR_
\& header AS_GOOGLE eval:check_asn(\*(Aq/\ebGoogle\eb/i\*(Aq, \*(AqMYASN\*(Aq)
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This plugin uses \s-1DNS\s0 lookups to the services of an external \s-1DNS\s0 zone such
as at \f(CW\*(C`http://www.routeviews.org/\*(C'\fR to do the actual work. Please make
sure that your use of the plugin does not overload their infrastructure \-
this generally means that \fByou should not use this plugin in a
high-volume environment\fR or that you should use a local mirror of the
zone (see \f(CW\*(C`ftp://ftp.routeviews.org/dnszones/\*(C'\fR).  Other similar zones
may also be used.
.PP
GeoDB (GeoIP \s-1ASN\s0) database lookups are supported since SpamAssassin 4.0 and
it's recommended to use them instead of \s-1DNS\s0 queries, unless \f(CW\*(C`_ASNCIDR_\*(C'\fR
is needed.
.SH "TEMPLATE TAGS"
.IX Header "TEMPLATE TAGS"
This plugin allows you to create template tags containing the connecting
\&\s-1IP\s0's \s-1AS\s0 number and route info for that \s-1AS\s0 number.
.PP
If you use add_header as documented in the example before, a header field is
added that looks like this:
.PP
.Vb 1
\& X\-Spam\-ASN: AS24940 213.239.192.0/18
.Ve
.PP
where \*(L"24940\*(R" is the \s-1ASN\s0 and \*(L"213.239.192.0/18\*(R" is the route
announced by that \s-1ASN\s0 where the connecting \s-1IP\s0 address came from.
If the \s-1AS\s0 announces multiple networks (more/less specific), they will
all be added to the \f(CW\*(C`_ASNCIDR_\*(C'\fR tag, separated by spaces, eg:
.PP
.Vb 1
\& X\-Spam\-ASN: AS1680 89.138.0.0/15 89.139.0.0/16
.Ve
.PP
Note that the literal \*(L"\s-1AS\*(R"\s0 before the \s-1ASN\s0 in the _ASN_ tag is configurable
through the \fIasn_prefix\fR directive and may be set to an empty string.
.PP
\&\f(CW\*(C`_ASNCIDR_\*(C'\fR is not available with local GeoDB \s-1ASN\s0 lookups.
.SH "BAYES"
.IX Header "BAYES"
The bayes tokenizer will use \s-1ASN\s0 data for bayes calculations, and thus
affect which BAYES_* rule will trigger for a particular message.  No
in-depth analysis of the usefulness of bayes tokenization of \s-1ASN\s0 data has
been performed.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
http://www.routeviews.org/ \- all data regarding routing, ASNs, etc....
.SH "ADMINISTRATOR SETTINGS"
.IX Header "ADMINISTRATOR SETTINGS"
.IP "asn_lookup asn\-zone.example.com [ _ASNTAG_ _ASNCIDRTAG_ ]" 4
.IX Item "asn_lookup asn-zone.example.com [ _ASNTAG_ _ASNCIDRTAG_ ]"
Use this to lookup the \s-1ASN\s0 info in the specified zone for the first external
IPv4 address and add the \s-1AS\s0 number to the first specified tag and routing info
to the second specified tag.
.Sp
If no tags are specified the \s-1AS\s0 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.
.Sp
If two or more \fIasn_lookup\fRs 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 \s-1AS\s0
number tag and the routing info tag.
.Sp
Examples:
.Sp
.Vb 1
\&  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_
.Ve
.IP "asn_lookup_ipv6 asn\-zone6.example.com [_ASN_ _ASNCIDR_]" 4
.IX Item "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.
.IP "clear_asn_lookups" 4
.IX Item "clear_asn_lookups"
Removes any previously declared \fIasn_lookup\fR entries from a list of queries.
.IP "asn_prefix 'prefix_string'       (default: '\s-1AS\s0')" 4
.IX Item "asn_prefix 'prefix_string' (default: 'AS')"
The string specified in the argument is prepended to each \s-1ASN\s0 when storing
it as a tag. This prefix is rather redundant, but its default value '\s-1AS\s0'
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.
.IP "asn_use_geodb ( 0 / 1 )          (default: 1)" 4
.IX Item "asn_use_geodb ( 0 / 1 ) (default: 1)"
Use Mail::SpamAssassin::GeoDB module to lookup \s-1ASN\s0 numbers.  You need
suitable supported module like GeoIP2 or GeoIP with \s-1ISP\s0 or \s-1ASN\s0 database
installed (for example, add EditionIDs GeoLite2\-ASN in GeoIP.conf for
geoipupdate program).
.Sp
GeoDB can only set _ASN_ tag, it has no data for _ASNCIDR_.  If you need
both, then set asn_prefer_geodb 0 so \s-1DNS\s0 rules are tried.
.IP "asn_prefer_geodb ( 0 / 1 )       (default: 1)" 4
.IX Item "asn_prefer_geodb ( 0 / 1 ) (default: 1)"
If set, \s-1DNS\s0 lookups (asn_lookup rules) will not be run if GeoDB successfully
finds \s-1ASN.\s0 Set this to 0 to get _ASNCIDR_ even if GeoDB finds _ASN_.
.IP "asn_use_dns ( 0 / 1 )            (default: 1)" 4
.IX Item "asn_use_dns ( 0 / 1 ) (default: 1)"
Set to 0 to never allow \s-1DNS\s0 queries.