[mrtg] Mrtg can determine interface on router after Wan interface went down.

Thu Aug 21 21:28:02 CEST 2008

I had a wan circuit failure early this morning at a site I monitor and
started getting the normal snmp no response message, that is until the
circuit came back active (router was never rebooted). when the wan
circuit came active is started receiving the following messages.  what
is wrong and what will correct this?

Normal Message when wan circuit is down.
See below for problem message

SNMP Error:

no response received

SNMPv2c_Session (remote host: "10.1.48.254" [10.1.48.254].161)

community: "xxxxxxx"

request ID: 83373349

PDU bufsize: 8000 bytes

timeout: 2s

retries: 5

backoff: 1)

at /usr/bin/../lib64/mrtg2/SNMP_util.pm line 491 SNMPGET Problem for
ifName.1 ifInOctets.1 ifName.1 ifOutOctets.1 on
xxxxx at 10.1.48.254:::::2:v4only at /usr/bin/mrtg line 2202

2008-08-21 02:30:06: WARNING: Could not match
host:'xxxxx at 10.1.48.254:::::2' ref:'Name' key:'Se0/0/0'

2008-08-21 02:30:06: WARNING: Could not match
host:'xxxxx at 10.1.48.254:::::2' ref:'Name' key:'Fa0/0'

2008-08-21 02:30:06: WARNING: Could not match
host:'xxxxx at 10.1.48.254:::::2' ref:'Name' key:'Se0/0/0.3'

2008-08-21 02:30:06: WARNING: Could not match
host:'xxxxx at 10.1.48.254:::::2' ref:'Name' key:'Se0/0/0.4'

2008-08-21 02:30:06: WARNING: Could not match
host:'xxxxx at 10.1.48.254:::::2' ref:'Name' key:'Se0/0/0.700'

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0][_IN_] '
$target->[129]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0][_OUT_] '
$target->[129]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_fa0_0][_IN_] '
$target->[130]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_fa0_0][_OUT_] '
$target->[130]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0.3][_IN_] '
$target->[131]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0.3][_OUT_] '
$target->[131]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0.4][_IN_] '
$target->[132]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0.4][_OUT_] '
$target->[132]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0.700][_IN_] '
$target->[133]{$mode} ' did not eval into defined data

2008-08-21 02:30:42: ERROR: Target[10.1.48.254_se0_0_0.700][_OUT_] '
$target->[133]{$mode} ' did not eval into defined data

Problem message After wan circuit becomes active

2008-08-21 12:05:06: WARNING: Can not determine ifNumber for
xxxxx at 10.1.48.254:::::2 ref: 'Name' key: 'Fa0/0'

2008-08-21 12:05:06: WARNING: Can not determine ifNumber for
xxxxx at 10.1.48.254:::::2 ref: 'Name' key: 'Se0/0/0.3'

2008-08-21 12:05:06: WARNING: Can not determine ifNumber for
xxxxx at 10.1.48.254:::::2 ref: 'Name' key: 'Se0/0/0.4'

2008-08-21 12:05:06: WARNING: Can not determine ifNumber for
xxxxx at 10.1.48.254:::::2 ref: 'Name' key: 'Se0/0/0.700'

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_fa0_0][_IN_] '
$target->[130]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_fa0_0][_OUT_] '
$target->[130]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_se0_0_0.3][_IN_] '
$target->[131]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_se0_0_0.3][_OUT_] '
$target->[131]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_se0_0_0.4][_IN_] '
$target->[132]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_se0_0_0.4][_OUT_] '
$target->[132]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_se0_0_0.700][_IN_] '
$target->[133]{$mode} ' did not eval into defined data

2008-08-21 12:05:19: ERROR: Target[10.1.48.254_se0_0_0.700][_OUT_] '
$target->[133]{$mode} ' did not eval into defined data

Was this mrtg getting messed up or does this maybe indicate a issue with
the router ?

Please not that during this period mrtg did record activity for Se0_0_0
.

I tried to correct this problem by rebuilding the cfg file but it did
not resolve the issue until I built the cfg file using snmp version 1 in
place of version 2.

Any insights on possible causes would be appreciated.

________________________________

From: mrtg-bounces at lists.oetiker.ch
[mailto:mrtg-bounces at lists.oetiker.ch] On Behalf Of Hughes, Andy
Sent: Thursday, August 21, 2008 12:15 PM
To: 'mrtg at lists.oetiker.ch'
Subject: Re: [mrtg] Newbie question

Steve, thanks very much for the response.  I will pursue what you have
suggested.

I did search for some error logs but found none. Where are they hiding?

Is mrtg by default going to run every 5 minutes without my intervention,
or are you saying I should change the task to run every 5 minutes
instead rather than the 10 I set up?

Thanks again!

________________________________

From: Steve Shipway [mailto:s.shipway at auckland.ac.nz] 
Sent: Monday, August 18, 2008 6:25 PM
To: Hughes, Andy; 'mrtg at lists.oetiker.ch'
Subject: RE: Newbie question

There are two problems here.

First, you are running data collection every 10 minutes.  Unless you
initially set the Interval to be 10, then this will mean you have 50% of
your data unknown, since you are (by default) supposed to poll every 5
minutes.  As your have a default XFF of 0.5 this can result in all your
data becoming 'unknown'.

Secondly, your data polling may be failing - but its hard to say as I
don't know what you're monitoring.  Possibly one of your monitored
devices is down, or unreachable, or the community string is wrong?
Check your error logs.  If you are failing to poll, or the poll is
taking >5min, then you will get unknowns stored.  The Routers2 frontend
will show this as a grey block to indicate 'data unknown' or 'device
unpollable', but native MRTG (and 14all) will default to the
'unknasprev' option (see below)

Now, if you have the 'unknasprev' option set in Routers2, or you are
using native MRTG (which does unknasprev by default), then 'unknown'
data will be displayed as the last known good value.  In your case, you
may have mostly unknowns, so you'd get a single, flat, solid green area.
This appears to be what's happening.  If the time on the x-axis is
changing, then you know your graph is being re-created, but the polling
is failing and the unknasprev option is just logging the last known good
value.

Check your polling.  Probably, the SNMP community has changed, or the
network is not working the same, or there is another problem.  Run the
MRTG poll from the command line to see if there are any obvious error
messages.  Make sure your polling is really running.  Schedule it every
5 mins instead of every 10 mins so the XFF (see the RRDtool
documentation) doesn't log everything as zero.

Good luck...

Steve

________________________________

From: mrtg-bounces at lists.oetiker.ch
[mailto:mrtg-bounces at lists.oetiker.ch] On Behalf Of Hughes, Andy

I installed mrtg two weeks ago to monitor traffic to/from an individual
router. All seemed to be well; I watched the graphs move as the week
went on etc.  For some reason, the graph no longer moves at all (i.e. no
peaks and valleys)--the entire thing is just solid green.  

I run mrtg every 10 minutes by a scheduled task that calls a batch file
in the \bin directory (Server 2003) that has a single line: perl mrtg
mrtg.cfg  I notice that when I was on the server initially when mrtg was
running properly, the command window would briefly flash when the batch
file ran. Now it stays open much, much longer before disappearing?

Please consider the environment before printing this e-mail.

CONFIDENTIAL NOTICE:
This e-mail message and any attachment(s) (collectively, this 'Email') are intended
only for the confidential use of the recipient(s) named above. If the reader of this
message is not the intended recipient named above or an agent responsible for
delivering it to the intended recipient named above, you have received this Email in error.
Please notify the sender immediately and permanently delete this Email and any copies thereof.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.oetiker.ch/pipermail/mrtg/attachments/20080821/1d1f5603/attachment-0001.html 