[mrtg] Customizing MRTG

Daniel McDonald dan.mcdonald at austinenergy.com
Tue Aug 3 14:59:31 CEST 2010

On 8/3/10 7:23 AM, "Bhupen" <go4bhupen at gmail.com> wrote:

> I am using MRTG version-2.9.17
I'm sorry.  That is a very old and probably buggy version.  2.16.mumble has
been out for a while now.

> Whenever, the target fails to execute (say, the service is not running),
> MRTG puts the output as -1. My requirement is that I get value 0, whenever
> the target fails to execute.

Options[]: unknownaszero
Should do the trick,
>                 To fix the issue, I need to modify the MRTG code ( bin/mrtg
> script).
Ok, if you think so.

>                 Did anyone do any customization to MRTG code?

Sure, lots.

> If so, what is
> the process you followed?

I came up with a plan, made my edits, tested, then discussed the changes on
the mailing list before sending a copy of the patch to Tobi.  Sometimes I'd
discuss a few ideas with other users before hacking at the code mercilessly.

Backwards compatibility is key, so creating new options or directives that
don't conflict with the original, but still follow the same spirit, are
quite important.

> Is there any licensing restrictions customizing
> MRTG code?

It's GPL, so you are free to do pretty much whatever you like, as long as
you include the GPL license in any distribution.  It's also polite to send
patches back to the maintainer, and give Tobi credit for creating the

Daniel J McDonald, CCIE # 2495, CISSP # 78281

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