Check for a specific IP and if not then send alert

[jkinning]

I have an Exchange cluster, don't know much about it, but the Exchange admin asked if Nagios can monitor the DAG cluster. There are 3 here in the Home Office using 10.131.x.x addresses and 1 in our DR site using 10.115.x.x. If this DAG ever gets a 10.115.x.x address a notification should be sent to them so they can correct the group so the 10.131.x.x is the primary online system.

Has anyone setup such a check or is there a better way to accomplish this monitoring.

[cdienger]

Is it really for a specific IP or is it for a range? If you want to check for a specific IP a simple check-host-alive check would do this.

Another option would be to configure the client to use a custom script that just sends it's IP address to Nagios. Assuming that DNS is updated when the client gets a new IP and Nagios, the check would come in via the correct hostname but with an alert that the IP has changed.

[jkinning]

In this case a range. I don't want it to have the 10.115 address. If it does I want a notification so I can change it back to a 10.131 address.

[tgriep]

Have you tried the DNS Query Wizard?
You put in the hostname and the expected IP addresses and it they are not correct, it will generate an alert.

[jkinning]

But in this case this host would be alright if it has one of 2 different IP addresses. The 10.131 network is alright but if it has the 10.115 I need to send out a notification. Is there a way to check and say if the host has the 10.115 address send out the notification since the other options would be OK, using the 10.131.

[tgriep]

That is what the check_dns plugin does, you give it a host name to look up and if the expected IP address is not returned, it will generate a Critical Alert.

This example is checking www.google.com for it to return the IP address of 172.217.8.196 and it did and the check was IP.

Code: Select all

/usr/local/nagios/libexec/check_dns -H www.google.com -a 172.217.8.196
DNS OK: 0.038 seconds response time. www.google.com returns 172.217.8.196|time=0.038112s;;;0.000000

I ran it again and it did not get the expected IP address and it generated a Critical Alert.

Code: Select all

/usr/local/nagios/libexec/check_dns -H www.google.com -a 172.217.8.196
DNS CRITICAL - expected '172.217.8.196' but got '172.217.8.164'

You would use the hostname for your cluster and the IP address 10.131 as the expected address.

[jkinning]

This will work. Thanks for the assistance and you can close this one.