The OP is not likely interested in monitoring software advocacy, he wants "a quick & dirty way to guarantee a good nights sleep" while his buddy is on vacation.

The OP is not likely interested in monitoring software advocacy, he wants "a quick & dirty way to guarantee a good nights sleep" while his buddy is on vacation. I still think a smart wrapper around check_tcp is the way to do this. Perhaps not out of cron, it can instead be a long running process in a sleep/fork/exec(check_tcp)/waitpid loop.