Scrutinize is an extensible misconfiguration scanner--not a vulnerability scanner,
use Metasploit for that--written using Twisted. It checks for common misconfigurations
such as allowing DNS Zone Transfer for your domain, not having a PTR record, or
allowing read access to your configuration files.

Usage examples:
  * python domainscan.py domain.com
  * python domainscan.py domain1.com domain2.com [...]
  * python hostscan.py host.domain.com
  * python hostscan.py host1.domain.com host2.domain.com [...]

More information:
  * python domainscan.py -h
  * python hostscan.py -h

  To improve performance, increase the throttle limit with the -t switch, or
  set throttle in config.py. If you experience excessive connection timeouts,
  lower it.

Extending:
  Write a module in checks/, then add that to the top of either hostscan.py or
  domainscan.py. (Improving this process is at the top of my to-do list.)