Fact: domain
Purpose:
Return the host's primary DNS domain name.
Resolution:
On UNIX (excluding Darwin), first try and use the hostname fact, which uses the `hostname` system command, and then parse the output of that. Failing that, it tries the `dnsdomainname` system command. Failing that, it uses `/etc/resolv.conf` and takes the domain from that, or as a final resort, the search from that. Otherwise returns `nil`. On Windows uses the win32ole gem and winmgmts to get the DNSDomain value from the Win32 networking stack.
Caveats: