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 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.

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.

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.

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

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).

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

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).

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

urinsrhsbl NAME_OF_RULE rhsbl_zone lookuptype

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.

urinsrhssub NAME_OF_RULE rhsbl_zone lookuptype subtest

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.

urifullnsrhsbl NAME_OF_RULE rhsbl_zone lookuptype

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.

urifullnsrhssub NAME_OF_RULE rhsbl_zone lookuptype subtest

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.

tflags NAME_OF_RULE ips_only

Only URIs containing IP addresses as the "host" component will be matched against the named "urirhsbl"/"urirhssub" rule.

tflags NAME_OF_RULE domains_only

Only URIs containing a non-IP-address "host" component will be matched against the named "urirhsbl"/"urirhssub" rule.

ADMINISTRATOR SETTINGS

uridnsbl_max_domains N (default: 20)

The maximum number of domains to look up.

NOTES

The uridnsbl_timeout option has been obsoleted by the rbl_timeout option. See the Mail::SpamAssassin::Conf POD for details on rbl_timeout.