This is a quick program that I wrote to see if a given MX ip is blocked by
popular MX blacklisting services (through dnsbl.info)

Return code is (or should be) nagios compatible (0 -> ok, 2 -> critical, 3 ->
unknown)


Synopsis
========

Usage: dnsbl.py -s SERVER [options]

Options:
  -h, --help            show this help message and exit
  -d, --debug           Debug mode, prints out lot of garbage
  -s SERVER, --server=SERVER
                        MX server to check


Licence
=======

Public domain, do anything you want with the code.
The program is given WITHOUT ANY WARRANTY, no event the warranty that it will
work.

Mentions, feeback and improvments are welcome.