surblhost(1) USER COMMANDS surblhost(1)NAMEsurblhost - check if hostnames are blacklisted by surbl.org
SYNOPSISsurblhost [ options ] [ host(s) ]
DESCRIPTIONsurblhost will check if the given hostnames are blacklisted by
surbl.org. Blacklisting means that global spam mail contains links to
the given hostnames, and should therefore be avoided.
Although surbl.org is usually used in mail transfer agents for identi‐
fying spam, you can use it for a lot of other purposes.
OPTIONS
- Read hostnames from standard input, separated by newlines.
--check-whitelist
Explicitly checks each and every entry in the pre-compiled and
user-submitted whitelist against the SURBL lists.
This is good to check if the whitelist is indeed OK, especially
when you compile your own.
When you set up a system to use your own whitelist, it is suffi‐
cient to run this command every once in a while -- you should
*not* run it every time you check a host.
-h --help
Print help text.
--no-surbl
Do not use the default multi.surbl.org as hostname suffix when
doing DNS A record lookups. That means you have to specify your
hostnames in the form somewhere.com.multi.surbl.org, or simi‐
larly if you want to use other lookup providers than surbl.org.
This is the same as using --surbl=''.
--print-tlds
Print the two-level TLDs that are used for recognizing domains
such as co.uk.
--print-whitelist
Prints the predefined whitelist that is hardcoded into surbl‐
host. This list is derived from the SpamAssassin whitelist at
http://spamassassin.apache.org/full/3.1.x/dist/rules/25_uribl.cf
and is pretty safe to hard-code. The point of the whitelist is
to reduce the number of DNS lookups needed for common hostnames.
-q --quiet
Quiet output; useful when you just want to check the exit code
of the program to determine if the given host(s) are black‐
listed.
-r --recursive
Recursively checks all subdomains for a given host. Example:
If you submit sub2.sub1.somewhere.com to surblhost with this
option, the following domains will be checked for blacklisting:
sub2.sub1.somewhere.com, sub1.somewhere.com, somewhere.com.
Note that the SURBL.org guidelines says they will only list
somewhere.com, but this option has been implemented because some
TLD countrycodes are a bit tricky. This is the situation with
e.g. co.uk domains. If you want to check somewhere.co.uk, then
using the -s option will not work very well, as it will check
"co.uk" instead of "somewhere.co.uk". Using the recursive
options works around this.
-f --skip-whitelist
Skip checking hostnames against the whitelists. You should
almost never use this option, as the whitelist is designed to
reduce the number of DNS lookups for most common hostnames. See
--print-whitelist.
-s --strip-sub
Strips subdomains from the hostnames given on the commandline,
i.e. `surblhost -s foo.bar.com' will only check if bar.com is
blacklisted. Two-level TLDs are recognized, so if you check
www.somewhere.co.uk and use this option, then only some‐
where.co.uk will be looked up.
--surbl=...
Set the surbl suffix yourself. The default value is
multi.surbl.org, but you can use other provides to check against
blacklists at your will. You just have to be sure that the
returned IP-addresses are in the same format as given by the
surbl guidelines at http://www.surbl.org
--test Tests against a permanent testpoint, which should always be
blacklisted.
--tlds=file
Read two-level TLDs from given file. You should put one entry
per line. An example of a two-level TLD is "co.uk".
--tlds-add=file
Same as --tlds=file, but adds the contents of file to the list.
-v --verbose
Give verbose output. This is recommended to give a feel of what
is actually being done.
-V --version
Show program version and exit.
--whitelist=file
Reads whitelist from given file. You should put one entry per
line.
--whitelist-add=file
Same as --whitelist=file, but adds the contents to the
whitelist.
RETURN VALUES
Surblhost returns 0 when no of the hostnames are blacklisted. It
returns 1 for errors, and 2 when one or more sites are blacklisted.
EXAMPLE: USING WITH SCRIPTS
Here is a complete BASH script that uses the exit code from surblhost
to check the status of given hostnames:
#!/bin/bash
# Copyright (C) 2006, 2007 Christian Stigen Larsen
# This script is placed in the public domain.
if test "$#" == "0" ; then
echo "usage: lookup [ hostname(s) ]"
echo "looks up if hosts are blocked by surbl.org"
exit 1
fi
while test ! -z "${1}" ; do
echo -n "checking ${1} ... "
surblhost-q -r 2>/dev/null ${1}
if test "$?" == "2"; then
echo "blocked"
else
echo "not blocked"
fi
shift
done
echo ""
echo "for more information, see http://www.surbl.org/lists.html"
exit 0
BUGS
This is still an early release, so there should be some code bugs. Be
sure to report anything to the author below. If you have suggestions
or patches, the author will be very happy to hear from you.
AUTHOR
Christian Stigen Larsen <csl@sublevel3.org> -- http://csl.sublevel3.org
LICENSEsurblhost is distributed under the GNU General Public License v2.
version 0.8 April 9, 2007 surblhost(1)
