Check pf.conf sync

Project Notes

This check is particularly useful when managing a pair of redundant appliances which run pf to provide IP routing and/or filtering. The check takes two arguments: the addresses of each appliance. It then attempts to transfer the pf.conf (logging in as the netadmin user) to the local machine's /tmp and perform a diff (using pecl-xdiff) before finally returning the status to Nagios. The netadmin user should use passwordless ssh login, or the password may be set in the user's .netc.