Mail::SpamAssassin::PlUser:Contributed)Mail::SpamAssassin::Plugin::URIDNSBL(3)
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).
"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, 127.2.3.0/255.255.255.0, 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.
tflags NAME_OF_RULE ns
The 'ns' flag may be applied to rules corresponding to uridnsbl and
uridnssub directives. Host names from URLs will be mapped to their
name server IP addresses (a NS lookup followed by an A lookup),
which in turn will be sent to blocklists. This is a default when
neither 'a' nor 'ns' flags are specified.
tflags NAME_OF_RULE a
The 'a' flag may be applied to rules corresponding to uridnsbl and
uridnssub directives. Host names from URLs will be mapped to their
IP addresses, which will be sent to blocklists. When both 'ns' and
'a' flags are specified, both queries will be performed.
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".
perl v5.16.3 2014-Mail::SpamAssassin::Plugin::URIDNSBL(3)
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