URIDNSBL - look up URLs against DNS blocklists
loadplugin Mail::SpamAssassin::Plugin::URIDNSBL uridnsbl URIBL_SBLXBL sbl-xbl.spamhaus.org. TXT
This works by analysing message text and HTML for URLs, extracting the domain names from those, querying their NS records in DNS, resolving the hostnames used therein, and querying various DNS blocklists for those IP addresses. This is quite effective.
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).
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.
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.
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.
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
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).
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.
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
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
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).
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.
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 .
Note that, as with urirhsbl, you must also define a body-eval rule calling
check_uridnsbl() to use this.
Example:
urirhssub URIBL_RHSBL_4 rhsbl.example.org. A 127.0.0.4 urirhssub URIBL_RHSBL_8 rhsbl.example.org. A 8
Perform a RHSBL-style domain lookup against the contents of the NS records
for each URI. In other words, a URI using the domain foo.com will cause
an NS lookup to take place; assuming that domain has an NS of ns0.bar.com,
that will cause a lookup of bar.com.uriblzone.net. Note that hostnames
are stripped from both the domain used in the URI, and the domain in the
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, as with urirhsbl, you must also define a body-eval rule calling
check_uridnsbl() to use this.
Specify a RHSBL-style domain-NS lookup, as above, 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). subtest is the sub-test to run against the returned data; see
<urirhssub>.
Note that, as with urirhsbl, you must also define a body-eval rule calling
check_uridnsbl() to use this.
Perform a RHSBL-style domain lookup against the contents of the NS records for
each URI. In other words, a URI using the domain foo.com will cause an NS
lookup to take place; assuming that domain has an NS of ns0.bar.com, that
will cause a lookup of ns0.bar.com.uriblzone.net. Note that hostnames are
stripped from the domain used in the URI.
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, as with urirhsbl, you must also define a body-eval rule calling
check_uridnsbl() to use this.
Specify a RHSBL-style domain-NS lookup, as above, 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). subtest is the sub-test to run against the returned data; see
<urirhssub>.
Note that, as with urirhsbl, you must also define a body-eval rule calling
check_uridnsbl() to use this.
Only URIs containing IP addresses as the "host" component will be matched against the named "urirhsbl"/"urirhssub" rule.
Only URIs containing a non-IP-address "host" component will be matched against the named "urirhsbl"/"urirhssub" rule.
The maximum number of domains to look up.
The uridnsbl_timeout option has been obsoleted by the rbl_timeout
option. See the Mail::SpamAssassin::Conf POD for details on rbl_timeout.