Port Status Check Configuration

[Rizal Muttaqin]

Hello all,

It's my first experience to play with monit. So, basically I have two 
server with several services running there and I want monit to check 
whether some ports (relative to that service) are listening or not with 
monit. The configuration relatively simple, monit check port status, 
when failed monit will start a nmap script bash script and send the 
status to the file. Plus, in same function, monit will send alert in 5 
cycles.

The problem is when monit send an connections failed alert then in the 
next 5 minutes monit send again an connection suceeded alert, when I 
check the nmap log script there's no port failed (filtered or 
close)/port status is always open. I've checked manually with nmap when 
monit send failed alert but the result is always the same: port status 
is open:


Why monit do always send failure alert when the port is open, and why in 
the next 5 minutes interval I see connection succeeded? I've changed set 
daemon to 30, and then the alert interval become 1.5 minutes, and revert 
daemon to be 300, but now the alert interval is always be 1.5 minutes.

This is my /etc/monitrc configuration for first server (another server 
configuration script exactly the same)


#####################################################

set daemon  300              # check services at 300 seconds (5 minutes) 
intervals

check host somehost with address somehost.com
        start program = "/opt/monit/scripts/checkport.sh start"
        stop program = "/opt/monit/scripts/checkport.sh stop"
        if failed port 80 then restart
        if failed port 843 then restart
        if failed port 2121 then restart
        if failed port 8080 then restart
        if failed port 80 for 5 cycles then alert
        if failed port 843 for 5 cycles then alert
        if failed port 2121 for 5 cycles then alert
        if failed port 8080 for 5 cycles then alert
        alert address@hidden with reminder on 5 cycles

########################################################

and this is my /opt/monit/checkport.sh script

########################################################

#!/bin/bash

case $1 in
 start)
        nmap -p 80,843,2121,8080 -P0 somehost.com -oG-| awk 'NR>=6 && 
NR<=9 {print $1 "\t" $2}' | cat >> /opt/monit/log/checkedport | date >> 
/opt/monit/log/checkedport & echo $! > /var/run/checkport.pid ;
        ;;
 stop)
   pkill -F /var/run/checkport.pid ;;
 *)
   echo "usage: checkport {start|stop}" ;;
esac
exit 0
#########################################################