Fix hostname detection
Currnetly, Sys::Hostname returns the short host name, or only the host part of the FQDN. For hosts that are properly named, naming only the host in /etc/hostname, etc, this causes confusion for hosts on their own subdomains, such as a.www.domain.com or a.ns.domain.com. Both these hosts require setting up rules for host 'a'. Instead, Sys::Hostname::FQDN should be used to get the full hostname.