[mrtg] Help with MRTG.cfg

Niall O'Reilly niall.oreilly at ucd.ie
Tue Jun 16 12:19:41 CEST 2020

On 16 Jun 2020, at 6:11, Brian Chernish wrote:

> After a bunch of Google searches I came up with the following which 
> creates the web page but does not seem to pull the actual data from 
> the switch.
> Any assistance in helping me understand where I am going wrong would 
> be appreciated.

I'm guessing that the web page is showing empty or flatline graphs;
is that the case?

The extract you sent from your configuration doesn't include the
global options, so I'm also guessing that you're using a log file
rather than an RRD database for saving the (non-) data.

If so, you can display the log file in your browser by substituting
'.log' for '.html' in the URL for page with the four (daily, weekly,
monthly, yearly) graphs.  If the top line of this file shows a
timestamp followed by '-1', it means that MRTG couldn't get the
data for the specified OIDs from the switch.

If all that matches, you might need to check which parts of the OID
tree are exposed for the 'public' community string, and adjust the
access as appropriate.

I've found it useful on many occasions when debugging this kind of
problem to have the Net-SNMP package installed, and use snmpwalk
from a shell session to confirm that the switch is actually
responding to SNMP requests for the OIDs of interest.

I hope this helps.

Niall O'Reilly

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