this is obsolete doc -- see http://doc.nethence.com/ instead

Self made monitoring 

Create a user account on the target server, 

useradd -m monitor

passwd monitor

Make it possible to connect throught SSH without password to that server, from a monitoring server. 

Each night on a monitoring server, add this script to crontab, 

#!/bin/ksh

# no set -e, proceed anyways

[[ ! -x `whence wc 2>/dev/null` ]] && print "wc executable not found" && \

        exit 1

tmp=`mailq`

[[ $tmp = "Mail queue is empty." ]] || print "$tmp"

unset tmp

tmp=`pgrep postoffice`

tmpwcl=`echo "$tmp" | wc -l`

(( tmpwcl == 2 )) || print "$tmp"

unset tmp tmpwcl

find /var/spool/virtual | grep .lock$

tmp=`pgrep vm-pop3d`

tmpwcl=`echo "$tmp" | wc -l`

(( tmpwcl == 3 )) || print "$tmp"

unset tmp tmpwcl