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Re: [nv-l] Netmon issue after FP04 installation

To: nv-l@lists.us.ibm.com
Subject: Re: [nv-l] Netmon issue after FP04 installation
From: James Shanks <jshanks@us.ibm.com>
Date: Wed, 19 Apr 2006 08:34:24 -0400
Delivery-date: Wed, 19 Apr 2006 13:34:54 +0100
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In-reply-to: <01a201c66381$8aaa5eb0$153c0a0a@ustr.com>
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 If you think this problem is unique to FP04, or even FP03 and FP04, then
you'll have to talk to Support.   They are the only ones who can
investigate what's different in the code internally.

But there could be other explanations for your issues, I think.

In my view, netmon, and indeed all of NetView, is extremely sensitive to
name resolution issues and always has been.  You'll find countless postings
in the archives about the problems caused by bad name resolution.

Names have to be resolved from addresses and addresses back into names for
every operation netmon does.  trapd is the same way.  snmpCollect  does
too.  And all NetView processes resolve names in exactly the same way, with
gethostbyname and gethostbyaddr, which are operating system calls.  They
wait for an answer while Microsoft does the name resolution.    And you can
affect this with a large ~/etc/hosts file, or by having a  number of
domains to search, or even by how your DNS people configure the name
server.    Are you sure they don't try to resolve a bad name by going to
other servers, or even externally to the Internet?

James Shanks
Level 3 Support  for Tivoli NetView for UNIX and Windows
Tivoli Software / IBM Software Group


                                                                           
             "Senny M"                                                     
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                                       [nv-l] Netmon issue after FP04      
             04/19/2006 03:19          installation                        
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Hi there,

I use Netview 7.1.4 with FP04 on Windows 2003 environment.

I found some inconsistency with netmon which is, more often Netmon Daemon
become so busy and doesn’t allow to status poll any other devices. When I
do a demand poll I am returned with a error “Waiting for Netmon to Respond
”.  This is purely after FP04 installation. The below given are my findings
after detailed look in Netview in my network environment.

When I do a demand poll to a device (Router or RSM), it runs normal till
the stage where “Verify node Name” polling happens. At this stage netmon
gets stuck and holds the Netmon busy without releasing. Then I found
Netview detected a name for my device which is wrong as well as the name,
which holds an IP address that is unreachable at all. This makes netmon to
confuse and makes it busy till it comes to some conclusion. But interesting
finding is that Netmon is getting released after exactly 15 min time and I
found this time gap by enabling the netmon trace (Netmon –M -1).

Now I deleted this problematic device out from Netview map and then added
the proper hostname and rediscovered it. Now Netmon is running without any
issue. So we can conclude that the problem is purely with DNS name
resolution in my environment.

Funniest part is that, this problem occurs only with FP04. Without FP04
(Base Netview 7.1.4) netmon is not trying to resolve the name if it could
not map the device with any IP (Including for this problematic device), and
immediately it releases saying “Node name was not found”.

Can anyone help me finding why this DNS problem raised after FP04
installation? What is the relevance of 15 min with netmon? I think this is
the case also with FP03 as well.

Regards,
Senny


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