Re: AW: polling problem

1999-01-13 16:43:26
Subject: Re: AW: polling problem
From: Dean Grant <dgrant AT AHOLDUSA DOT COM>
To: nv-l AT lists.tivoli DOT com
Date: Wed, 13 Jan 1999 16:43:26 -0500
We ran into the same problem with NetView 4.1.2. What we discovered is the
fact that NetView does not treat nodes the same between up and down polling
cycles. We used a sniffer, and we observed that  if a non-snmp node is
known to be Up by NetView, it would send an ICMP C Get Address Mask. If the
same node was known to be Down, it would send a ICMP Echo only.

Some devices on the network would not respond to the ICMP C Get Address
Mask , so NetView flagged it as being down. On the next polling cycle, the
ICMP Echo was sent and the device was back up.

The problem was solved by using an (as far as I know) undocumented daemon
option for Netmon. We added a "-x" to the /usr/OV/lrf/netmon.lrf file on
the NetView server. This option told the Netmon daemon not to perform the
ICMP C Get Address Mask request to non-snmp devices when attempting to get
configuration information. We had to work this one out with the support

Don't know if this is the exact problem you are seeing, but I suspect it is

Mearl Danner <jmdanner AT SAMFORD DOT EDU> on 01/13/99 04:16:12 PM

Please respond to Discussion of IBM NetView and POLYCENTER Manager on

cc:    (bcc: Dean Grant/AIS/US/Ahold)
Subject:  Re: AW: polling problem

We use NV6000 4.1.2 on an RS6000 running AIX 4.2.1.

We have been having similar problems with our network also.
It apparently was due to some problems with the bridging
tables in our 3Com 2500 layer 3 switches. Since we upgraded
the software in the 2500s to the latest release (,
I haven't had a node down event I couldn't reconcile to an
obvious hardware problem.

You didn't specify what hardware you are pinging through,
but this is one possibility. It also seems that the pinging
that Netview does operates under different rules than the
command line ping. I can never see any problems using the
command line ping or the pulldown from the GUI. The device
always came back up on the next ping cycle.

On Wed, 13 Jan 1999 09:47:42 -0600 Stephane Robertson
<Stephane.Robertson AT HEC DOT CA> wrote:

> > I don4t know where this problem belongs to, so I post it here and hope
> > it is known by someone:
> > We4re using NK 5.1 on AIX4.2.1. From time to time I see Interface down
> > node down events from active stations. When looking on the network I
see an
> > ARP request to the station, which isn4t answered. When I ping these
> > stations from command line, Interface and node up events are shown.
> > I know, this seems to be a network problem, but there was never a
> > ping which wasn4t answered. Only the pings from NetView fail.
> > Thanks in advance for any help!
> >
> > Mario
> Mario,
> Do you an ATM Network?
> Did you see the ping request on the server side?
> I had the same problem and I fixed it by putting very small timeout and
> retries.
> Since I changed to that setting I don't have any problem but I don't
think the
> problem
> is really fixed. Can you send me what kind of device you have to compare
> my network because I also suspect something on the network. May be we
> something
> in common that could point us to the solution.
> SR
> --
> Stephane Robertson
> Ecole des Hautes Etudes commerciales
> 3000 chemin de la cote-sainte-catherine
> Montreal, Quebec
> H3T 2A7
> E-Mail: Stephane.Robertson AT hec DOT ca
> Phone : 514-340-6560
> Fax   : 514-340-5637
> Windows 98 supports real multitasking - it can boot and crash

Mearl Danner
Network Engineer
Email: jmdanner AT samford DOT edu
Samford University

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