Nagios Support Forum

For customers in which we manage both the circuit and the firewall, we would like to ping the inside loopback IP of the connected device and all outside public IPs of the firewall. This is because we need visibility into what is actually unreachable. Is this possible? If yes, Please share some details how to do it. In addition to ICMP ping, can we have polling? If yes, please share some details how to do it.

Just to clarify, you'd like to have Nagios ping the loopback address for the Firewall correct?

Check_icmp should be all you need, in conjunction with check_by_ssh / check_nrpe depending on your firewall specifications.

Firewall loopback ip address means the IP address which is assigned to a port and then a host is connected on that IP.
Is it possible to get a response of that IP address?

I've always understood loopback as a local address, specific to a machine, and not assigned to any interfaces / clients except virtually.

From the firewall, can you ping that IP from it?

Yes the IP address can be pinged from firewall..

I would look at using check_nrpe or check_by_ssh then so that you can run those commands locally on that machine as the loopback won't be accessible otherwise.

See these documents which outline on setting that up -
https://assets.nagios.com/downloads/nag ... ng_SSH.pdf
https://assets.nagios.com/downloads/nag ... g_NRPE.pdf

You'll then need to get check_icmp compiled on the Firewall, and create a command in the NRPE configuration file for it to use.