Mail::SpamAssassin::Plugin::URIDNSBL(3pm) - phpMan

Mail::SpamAssassin::Plugin::URIUserLContributed Perl DocMail::SpamAssassin::Plugin::URIDNSBL(3pm)

NAME
URIDNSBL - look up URLs against DNS blocklists

SYNOPSIS
loadplugin Mail::SpamAssassin::Plugin::URIDNSBL
uridnsbl URIBL_SBLXBL sbl-xbl.spamhaus.org. TXT

DESCRIPTION
This works by analysing message text and HTML for URLs, extracting host names from those,
then querying various DNS blocklists for either: IP addresses of these hosts (uridnsbl,a)
or their nameservers (uridnsbl,ns), or domain names of these hosts (urirhsbl), or domain
names of their nameservers (urinsrhsbl, urifullnsrhsbl).

USER SETTINGS
skip_uribl_checks ( 0 | 1 ) (default: 0)
Turning on the skip_uribl_checks setting will disable the URIDNSBL plugin.

By default, SpamAssassin will run URI DNSBL checks. Individual URI blocklists may be
disabled selectively by setting a score of a corresponding rule to 0 or through the
uridnsbl_skip_domain parameter.

See also a related configuration parameter skip_rbl_checks, which controls the DNSEval
plugin (documented in the Conf man page).

uridnsbl_skip_domain domain1 domain2 ...
Specify a domain, or a number of domains, which should be skipped for the URIBL
checks. This is very useful to specify very common domains which are not going to be
listed in URIBLs.

clear_uridnsbl_skip_domain [domain1 domain2 ...]
If no argument is given, then clears the entire list of domains declared by
uridnsbl_skip_domain configuration directives so far. Any subsequent
uridnsbl_skip_domain directives will start creating a new list of skip domains.

When given a list of domains as arguments, only the specified domains are removed from
the list of skipped domains.

RULE DEFINITIONS AND PRIVILEGED SETTINGS
uridnsbl NAME_OF_RULE dnsbl_zone lookuptype
Specify a lookup. "NAME_OF_RULE" is the name of the rule to be used, "dnsbl_zone" is
the zone to look up IPs in, and "lookuptype" is the type of lookup (TXT or A). Note
that you must also define a body-eval rule calling "check_uridnsbl()" to use this.

This works by collecting domain names from URLs and querying DNS blocklists with an IP
address of host names found in URLs or with IP addresses of their name servers,
according to tflags as follows.

If the corresponding body rule has a tflag 'a', the DNS blocklist will be queried with
an IP address of a host found in URLs.

If the corresponding body rule has a tflag 'ns', DNS will be queried for name servers
(NS records) of a domain name found in URLs, then these name server names will be
resolved to their IP addresses, which in turn will be sent to DNS blocklist.

Tflags directive may specify either 'a' or 'ns' or both flags. In absence of any of
these two flags, a default is a 'ns', which is compatible with pre-3.4 versions of
SpamAssassin.

The choice of tflags must correspond to the policy and expected use of each DNS
blocklist and is normally not a local decision. As an example, a blocklist expecting
queries resulting from an 'a' tflag is a "black_a.txt" (
http://www.uribl.com/datasets.shtml ).

Example:

uridnsbl URIBL_SBLXBL sbl-xbl.spamhaus.org. TXT
body URIBL_SBLXBL eval:check_uridnsbl('URIBL_SBLXBL')
describe URIBL_SBLXBL Contains a URL listed in the SBL/XBL blocklist
tflags URIBL_SBLXBL net ns

uridnssub NAME_OF_RULE dnsbl_zone lookuptype subtest
Specify a DNSBL-style domain lookup with a sub-test. "NAME_OF_RULE" is the name of
the rule to be used, "dnsbl_zone" is the zone to look up IPs in, and "lookuptype" is
the type of lookup (TXT or A).

Tflags 'ns' and 'a' on a corresponding body rule are recognized and have the same
meaning as in the uridnsbl directive.

"subtest" is a sub-test to run against the returned data. The sub-test may be in one
of the following forms: m, n1-n2, or n/m, where n,n1,n2,m can be any of: decimal
digits, 0x followed by up to 8 hexadecimal digits, or an IPv4 address in quad-dot
form. The 'A' records (IPv4 dotted address) as returned by DNSBLs lookups are
converted into a numerical form (r) and checked against the specified sub-test as
follows: for a range n1-n2 the following must be true: (r >= n1 && r <= n2); for a n/m
form the following must be true: (r & m) == (n & m); for a single value in quad-dot
form the following must be true: r == n; for a single decimal or hex form the
following must be true:
((r & n) != 0) && ((r & 0xff000000) == 0x7f000000), i.e. within 127.0.0.0/8

Some typical examples of a sub-test are: 127.0.1.2, 127.0.1.20-127.0.1.39,
127.0.1.0/255.255.255.0, 0.0.0.16/0.0.0.16, 0x10/0x10, 16, 0x10 .

Note that, as with "uridnsbl", you must also define a body-eval rule calling
"check_uridnsbl()" to use this.

Example:

uridnssub URIBL_DNSBL_4 dnsbl.example.org. A 127.0.0.4
uridnssub URIBL_DNSBL_8 dnsbl.example.org. A 8

urirhsbl NAME_OF_RULE rhsbl_zone lookuptype
Specify a RHSBL-style domain lookup. "NAME_OF_RULE" is the name of the rule to be
used, "rhsbl_zone" is the zone to look up domain names in, and "lookuptype" is the
type of lookup (TXT or A). Note that you must also define a body-eval rule calling
"check_uridnsbl()" to use this.

An RHSBL zone is one where the domain name is looked up, as a string; e.g. a URI using
the domain "foo.com" will cause a lookup of "foo.com.uriblzone.net". Note that
hostnames are stripped from the domain used in the URIBL lookup, so the domain
"foo.bar.com" will look up "bar.com.uriblzone.net", and "foo.bar.co.uk" will look up
"bar.co.uk.uriblzone.net".

If an URI consists of an IP address instead of a hostname, the IP address is looked up
(using the standard reversed quads method) in each "rhsbl_zone".

Example:

urirhsbl URIBL_RHSBL rhsbl.example.org. TXT

urirhssub NAME_OF_RULE rhsbl_zone lookuptype subtest
Specify a RHSBL-style domain lookup with a sub-test. "NAME_OF_RULE" is the name of
the rule to be used, "rhsbl_zone" is the zone to look up domain names in, and
"lookuptype" is the type of lookup (TXT or A).

Some typical examples of a sub-test are: 127.0.1.2, 127.0.1.20-127.0.1.39,
127.2.3.0/255.255.255.0, 0.0.0.16/0.0.0.16, 0x10/0x10, 16, 0x10 .