router's snmp return values/10 after 1GByte traffic reached

[human]

hi, I've used mrtg for years in my home routers without problem, until I changed to a D-LINK DSL-G624T... and I noticed that after some hours, the graphics suddenly drop. I investigated the problem, even with a sniffer, and I saw these two consecutive snmp network packets returned by the router (mrtg 5min interval):

...

Object identifier 1: 1.3.6.1.2.1.2.2.1.10.3 (IF-MIB::ifInOctets.3) Value: Counter32: 981764540

...

Object identifier 1: 1.3.6.1.2.1.2.2.1.10.3 (IF-MIB::ifInOctets.3) Value: Counter32: 100250466

...

So after this router reaches 1GByte of accumulated traffic in an interface, it counts only in amounts of (whahever/10)... as mrtg seems to unknow/undetect this, it makes the graphics as if only tenth of the traffic is being transmitted (that's what it really sees)... I'm using mrtg-2.9.22, and I haven't seen such a characteristic in any version of mrtg (just looked CHANGES file), so I don't know if it's a proper behavior or not.

is there any mrtg option to manage this situation (latest mrtg versions perhaps)? or, could I modify mrtg perl code in order to "patch" this? (just a hint of the file, and I could code and contribute it)

thank you for your time.

[human]

I've tried to use mrtg's manual indication about SNMPv2c; in my case, in mrtg.cfg: Target[192.168.1.1_3]: 3:public@192.168.1.1:::::2

But, though the router specs claim to support SNMPv2c ( ftp://ftp.dlink.es/Adsl/DSL-G624T/Data_sheet/DSL-G624T_Data%20Sheet.pdf), it returns NULL values (as seen with a sniffer (and also log states that the router hasn't understood it)):

Error Status: NO SUCH NAME (2) Error Index: 1 Object identifier 1: 1.3.6.1.2.1.31.1.1.1.6.3 (IF-MIB::ifHCInOctets.3) Value: NULL

So 64 bit counters aren't available...

any hint will be appreciated.

[human]

perl code (and readme.txt with help to install it)

[human]

As nobody seems to have this very same problem, I've created a small piece of code in order to patch it in my case. I've upload it here as: manage_DLINK_SNMP_behaviour.20070729.tgz

The tgz file contains a readme file with instructions, my pl code, and a modified mrtg v2.15.2.

nevertheless, I leave this open, just in case anyone want to add more info.

bye

[oetiker]

this 'bug' is too weired to have it fixed within mrtg. BUT what you could do, is to produce an external monitoring script which fixes the counter values prior to handing them to mrtg using the backtick target syntax (script).