Check ports - NRPE portaudit check

$ cat /usr/ports/net-mgmt/nagios-check_ports/pkg-descr
Nagios Plugin to monitor your FreeBSD Ports Tree for updates or
installed packages with known security vulnerabilities.

Install the port:

sudo portmaster /usr/ports/net-mgmt/nagios-check_ports/

Add the following line to /usr/local/etc/nrpe.cfg:

command[check_ports]=/usr/local/libexec/nagios/check_ports

And restart NRPE. Remember to add the check to the host on the Nagios server as well. In my install this is as simple as making the server a member of the freebsd_servers group.