Easy Web server monitoring tool SEC: UNCLASSIFIED

Paul Bryan paul at yahoo.co.uk
Thu Mar 6 20:53:00 EST 2003

On Tue, 11 Feb 2003 11:57, Cox, Neil wrote:
> NAGIOS -- http://www.nagios.org/

You could also have also have a look at Big Brother as well as Nagios (used 
to be called Netsaint). Both of these tools have a modular architecture ie. 
there is a main process that runs the checks on your hosts and collates 
responses, while  the checks themselves are modules eg. there is an ftp 
module, a http module etc.

Both come with a whole host of modules. You can check things like disk space, 
processor usage etc. Basically, each module can be passed parameters to 
determine what constitutes an okay, error or warning status. For example, for 
checking disk space you might specify 95% usage is an error, 80% is a warning 
and anything below is okay. For a http check, you can specify things like max 
timeout on the connection, does a 400 error constitute an error or  warning, 
and so on. Of course, you can configure this on a per host/service basis.

Both tools provide a web interface for checking the status of hosts/services, 
which also shows the history of your hosts/services. They also allow for 
certain events to trigger certain actions. For example, when your web server 
changes to an error status, an email can be sent notifying you, or it can 
attempt to restart the web server (this should be treated with caution 

I've personally used Netsaint before it became Nagios because I found it to 
be more configurable and customizable to my needs than Big Brother. Big 
Brother is also licensed under what they call a "better than free" license, 
which I can only describe as "not better than free". Basically, it's free for 
non-commercial use, but their definition of non-comercial is a little hazy. 
You make up your own mind.

Nagios is GPL, so it's quite easy to write your own modules, or modify 
existing ones to your needs. I modified the (Netsaint) http check to allow me 
to check a proxy server rather than a web server for example. Modules can be 
written in the language of your choice (with Netsaint anyway - I don't too 
much about ) which is very nice if your good with scripting but don't know 
much c.

Hope I haven't gone on too much again.


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