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

Marinos Chondrogiannoglou mchon at otenet.gr
Wed Feb 2 10:15:36 CET 2011

see my comments inline

On 02/02/2011 09:59 AM, Steve Shipway wrote:
> The .ok files do not cache the polling time, they only cache the interface identifiers.  When the .ok file is unavailable or empty, MRTG will walk the IF-MIB tree to read all the interface details which it then caches in the .ok file for next time (if it can) and it uses the interface details to map a reference (eg IP address) to an interface number.
> The polling time is handled by your scheduler (if you use a cron-based system) or by MRTG's own internal scheduler, which is based on the system clock, if you use daemon mode.

Exactly but when has to poll every time the if-mib it takes much more
time to finish each cfg file.

> Since your system works for a bit and then goes wrong, my guess is that something is causing a periodic reconfiguration of your underlying Serial interfaces and subinterfaces.  The only way to verify this would be to take an SNMP walk of the IF-MIB now, remove the .ok file and let the system work for a bit, and when itnext goes wrong take another SNMP walk and compare the two.  If they dont match, then you're getting reconfiguration. 
> Another possible solution would be to use a scheduler to regularly (daily?  weekly?) call cfgmaker and re-generate your .cfg files.  This would get around any problem with the configuration altering, though if you are using daemon mode you'd need to make sure you either restart the daemon or have MRTG 2.17 (which re-reads a changed config file)

The system at the moment runs in deamon mode and there is a mechanism
tha produces new config every time the routers configuration is updated.
I've compared the snmp walks and everything is ok.


Marinos Chondrogiannoglou
Network Management Center
99 Kifisias Av. Marousi
GR-151 24 Athens, HELLAS
PGP Key ID: 0x2EEFC190

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