Nagios plug-in for monitoring ISC DHCP

Sun Mar 18 16:59:27 UTC 2012

Why are you specifying two IP addresses?

Frank

From: dhcp-users-bounces+frnkblk=iname.com at lists.isc.org
[mailto:dhcp-users-bounces+frnkblk=iname.com at lists.isc.org] On Behalf Of
Loren M. Lang
Sent: Sunday, March 18, 2012 1:31 AM
To: Users of ISC DHCP
Subject: Re: Nagios plug-in for monitoring ISC DHCP

On 3/17/2012 6:11 PM, Joe Vitti wrote: 

This should be possible. 

You setup the nagios server as a host with a service for check_dhcp in the
nagios config. This will make it monitor itself. You might need the nrpe
client setup as well.

I am using NRPE client, but only for checks that need to be run on remote
servers like check_load.  For network protocols like DNS and DHCP, you can
just generate the test packets straight from the Nagios server and test it
like a real client!  Here's the command I have Nagios running:

/usr/bin/sudo /usr/lib/nagios/plugins/check_dhcp -s 192.168.1.5 -s
192.168.1.7 -i eth0

On the Nagios server, it returns this:

WARNING: Received 1 DHCPOFFER(s), only 1 of 2 requested servers responded,
max lease time = 1800 sec.

But on a third-party server that doesn't run DHCP, I get this:

OK: Received 2 DHCPOFFER(s), 2 of 2 requested servers responded, max lease
time = 1800 sec.

I'd prefer to have the Nagios server run the test and generate the packets
directly rather than rely on a third-party to be up and do the test for
Nagios.

_______________________________________________________________ 

Joe Vitti

Network and Systems Administrator

GCInfotech | 2009 Summer Street | Suite 302 | Stamford, CT 06905

p: 203.463.7209 | e: jvitti at gcinfotech.com

On Mar 17, 2012, at 9:07 PM, Loren M. Lang wrote:

I am using a Nagios plug-in called check_dhcp to monitor both my DHCP
servers.  It works by broadcasting a DHCPDISCOVER message and monitoring any
DHCPOFFERs.  It reports back a Warning status if not all DHCP servers
respond and a Critical status if no one responds.  The problem I am having
is that the Nagios server is running on the same hardware as one of the DHCP
servers and it does not seem to respond to the DHCPDISCOVER.  I can
successfully run the plug-in on a separate computer to get it to respond,
but I'd like to test it from the same server running all the Nagios checks.
Is it possible to send a DHCPDISCOVER to the daemon running on the same
computer without using a separate network card tied to the network?

-- 
Loren M. Lang
lorenl at north-winds.org
http://www.north-winds.org/

Public Key: ftp://ftp.north-winds.org/pub/lorenl_pubkey.asc
Fingerprint: 10A0 7AE2 DAF5 4780 888A  3FA4 DCEE BB39 7654 DE5B

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-- 
Loren M. Lang
lorenl at north-winds.org
http://www.north-winds.org/

Public Key: ftp://ftp.north-winds.org/pub/lorenl_pubkey.asc
Fingerprint: 10A0 7AE2 DAF5 4780 888A  3FA4 DCEE BB39 7654 DE5B
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