[mrtg] Can not determine ifNumber and duplicate entries of IP-Ifindex at the .ok files

Marinos Chondrogiannoglou mchon at otenet.gr
Tue Feb 1 07:30:54 CET 2011

Hello Steve,

Thanks for your answer. Indeed our problem seems to be the second one.
The permissions are ok and also mrtg can write in the .ok files and
create the duplicate entries. I was running 2.16.2 when the problem
started and I have upgrade it to the latest 2.17.0 last week but with no
change in it's behaviour.


On 01/31/2011 11:13 PM, Steve Shipway wrote:
>> 2011-01-31 13:24:01: WARNING: Can not determine ifNumber for
>> public at router:::2::1   ref: 'Ip'       key: ''
> This message means that it cannot work out how to (uniquely) determine which interface to monitor when it's been given the IP address as a key.
> This can be caused by 2 things --
> 1. There really ARE two interfaces with the same key.  In your case, this is not true, though it can happen in some cases, eg when a description or MAC address is used as a key.
> In this case, the solution is to use a different key to uniquely identify the interface.
> 2. The .ok cache file contains invalid data, that cannot be removed.  This is your problem.  This can be caused when the device is reconfigured, or new interfaces added etc, causing a reenumeration of the interfaces.  Possibly, the file is somehow undeleteable or not updateable (check permissions)?
> In this case, the solution is to DELETE THE .OK FILE, which will cause it to be re-created automatically with the correct data.  This should happen normally, but can sometimes get confused -- check you have the latest version of MRTG (or at least 2.16.2 )
> Steve
> Steve Shipway
> ITS Unix Services Design Lead
> University of Auckland, New Zealand
> Floor 1, 58 Symonds Street, Auckland
> Phone: +64 (0)9 3737599 ext 86487
> DDI: +64 (0)9 924 6487
> Mobile: +64 (0)21 753 189
> Email: s.shipway at auckland.ac.nz
>  Please consider the environment before printing this e-mail 

Marinos Chondrogiannoglou
Network Management Center
99 Kifisias Av. Marousi
GR-151 24 Athens, HELLAS
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