Check Host without Ping
There are many good reasons to disable ping on a server. Typically I disable ping (ICMP) on my servers and add a iptables entry to allow the nagios monitoring service complete access to monitor the system.
It is a good idea to disable ping since generally someone could use it to sniff out your open ports and find possible vulnerabilities.
Overview
As of this post I am running Nagios 3.2.0. Occasionally you might be checking a host that has ping (ICMP) disabled or just doesn’t respond to ping requests. As you can see from the image below because the ping response is blocked and Nagios reports an issue even though all services on the client are running prefectly. It just can’t ping it!
Solution
Submitting a passive check result can be done via the Web Interface (among other ways) so you just need to login to Nagios, select the host in question and use the “Submit passive check result for this host” command option from the list of Host Commands.
check_tcp -p 80
Now you have the ability to check a host that has PING response disabled while displaying the correct state status. All services check will continue as normal but now you can display the up or down status
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That only updates the status once. This template lets you define a host that only uses the web check to determine if the host is alive.
# Generic host definition template – This is NOT a real host, just a template!
define host{
name generic-noping-webhost ; The name of this host template
notifications_enabled 1 ; Host notifications are enabled
event_handler_enabled 1 ; Host event handler is enabled
flap_detection_enabled 1 ; Flap detection is enabled
failure_prediction_enabled 1 ; Failure prediction is enabled
process_perf_data 1 ; Process performance data
retain_status_information 1 ; Retain status information across program restarts
retain_nonstatus_information 1 ; Retain non-status information across program restarts
check_command ‘check_tcp -p 80′
max_check_attempts 10
notification_interval 0
notification_period 24×7
notification_options d,u,r
contact_groups admins
register 0 ; DONT REGISTER THIS DEFINITION – ITS NOT A REAL HOST, JUST A TEMPLATE!
}