RE: What happened to netmon Flag?

[Kuffer Andreas <Andreas.Kuffer@kuoni.ch>]

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Regarding to the loopback masks I absolutely agree with you. But...something
must have changed from 5.1.2 to 6.0 in the way netmon discovers loopback
interfaces since the "old" netview had no problems with them.
 
While trying around I finally discovered the device correctly (put the
loopback address into the seedfile) and after 2 or 3 trys it finally got
discovered. If as an alternative put a Lan-ip-address in the seedfile the
device gets discovered without the loopback interface. Even better, there is
no "loopback" object at all in the database. 
 
Leslie pointed out that it could be related to the location.conf file and
entries in the nettl.log. Next week I'll do more investigation on that topic
 

With kind regards / mit freundlichen Gruessen 
Andreas Kuffer (System Manager UNIX and Enterprise Management) 

-----Original Message-----
From: Sean Davidson [mailto:sean.davidson@mail.publix.com]
Sent: Freitag, Juli 07, 2000 16:38
To: 'IBM NetView Discussion'
Subject: RE: [NV-L] What happened to netmon Flag?


The loopback interface on a Cisco router and the loopback interface on a
standard TCP/IP machine (127.0.0.1) are two different things. The loopback
on a standard TCP/IP machine is typically used for communication between
processes on that machine. So a 255.255.255.255 mask is valid.
 
The loopback interface on a Cisco router is a software interface that only
drops when it is either intentionally shutdown or the router loses power.
Other than that, it is a just like any other interface on the router. You
have to give it a valid IP address with a valid subnet mask. 255.255.255.255
(network of all 1's) is never a valid TCP/IP subnet mask. There are no bits
left over for hosts. The loopback interface on the cisco router is typically
used to tie Cisco processes like DLSW,RSRB,BSTUN,STUN,etc...
 
If you have a primary and backup link on a router and you tie any of those
processes to a real physical interface, that process no longer functions
when the primary interface goes down and the backup link recovers the
connectivity. This is where the Cisco loopback interface is useful. It is
always up.
 
I don't believe the -L netmon flag you mention is the problem. Check the
MIB2 interface table reported by the router and see if the loopback
interface is there.
__________________________ 
Thanks, 
Sean Davidson 

Sr. Network Systems Engineer 
Publix Super Markets, Inc. 
P.O. Box 32015 
Lakeland, Fl. 33802-2015 
Email - sean.davidson@publix.com 
Voice - (863) 686-8754 x6889 
Fax - (863)616-5895 

 
 

-----Original Message-----
From: Kuffer Andreas [mailto:Andreas.Kuffer@kuoni.ch]
Sent: Friday, July 07, 2000 3:48 AM
To: 'IBM NetView Discussion'
Subject: RE: [NV-L] What happened to netmon Flag?



I checked the netmask of the loopback interface, it was indeed set to
255.255.255.252. I asked the network guys why and the answer was that in
earlier times you were not allowed (unable) to set a mask of
255.255.255.255. So the "loopback-netmask"-design of our network is
255.255.255.252 due to historical reasons.

Anyway we reconfigured the Cisco 1600 to 255.255.255.255, did a demand poll
and also a new discovery but received the same results as I posted before.

I will call support today but I'm still interested if there is anybody out
there with NetView 6.0 discovering loopback interfaces.

With kind regards / mit freundlichen Gruessen 
Andreas Kuffer (System Manager UNIX and Enterprise Management) 


-----Original Message----- 
From: lclark@us.ibm.com [ mailto:lclark@us.ibm.com
<mailto:lclark@us.ibm.com> ] 
Sent: Donnerstag, Juli 06, 2000 16:30 
To: IBM NetView Discussion 
Subject: Re: [NV-L] What happened to netmon Flag? 


The -L flag was dropped in V6 (made a no-op) because it was no longer 
needed. This is because, according to the internal update I attended, 
32-bit masks are now fully supported; 32-bit masks are generally used for 
software loopback interfaces. The connection is not exactly clear to me, 
but I have seen loopbacks discovered successfully in V6, whether the 
loopback was the address specified in the seedfile or not. So by my 
voodoo-problem-determination methodology, I would suggest checking 
the mask on the loopback that is missing. If it is not 255.255.255.255, 
make 
it so. If it is already so, look for some other, more mundane discovery 
problem, or  call Support with a trace of the discovery handy. 

Cordially, 

Leslie A. Clark 
IBM Global Services - Systems Mgmt & Networking 
Detroit 


Kuffer Andreas <Andreas.Kuffer@kuoni.ch>@tkg.com on 07/06/2000 04:59:40 AM 

Please respond to IBM NetView Discussion <nv-l@tkg.com> 

Sent by:  owner-nv-l@tkg.com 


To:   "'IBM NetView Discussion'" <nv-l@tkg.com> 
cc: 
Subject:  [NV-L] What happened to netmon Flag? 




AIX  4.3.2, NV 5.1.2 and NV 6.0 
in  version 6.0 of netview it seems that one flag of netmon (-L, discover 
loopback  interfaces with other address than 127.0.0.0) was withdrawn. 

I have  a Cisco 1600 with loopback interface 10.10.224.85 and three other 
interfaces 

Demand  poll with NV 5.1.2 (netmon runs with -L): 
Interface 10.10.232.86 (currently up)     responded to ping 

Interface 10.10.21.1 (currently up)    responded to ping 
Interface 10.10.224.85 (currently up)    responded to ping 
Interface 10.10.240.86 (down since 07/03/00)    ping timed  out 

Demand  poll with NV 6.0 shows: 
Interface 10.10.232.86 (currently up)     responded to ping 

Interface 10.10.21.1 (currently up)    responded to ping 

Interface 10.10.240.86 (down since 07/03/00)    ping timed  out 

So it looks like  netmon V6.0 doesn't discover the loopback interface I'd 
like to see. Does that  work as designed? Did I miss anything? Can I use an 
undocumented "-L  feature"? 

Any help  is very welcome...Andreas 

With kind regards / mit freundlichen  Gruessen 
Andreas Kuffer  (System Manager UNIX and Enterprise  Management) 

Kuoni Travel Ltd. 
Dep. TOU 
Neue Hard 7 
CH-8010 Zuerich 
Switzerland 
Telefon : + 41 1 277 52 41 
Fax     : + 41 1 272 52 55 

<<< the smile that you send out  returns to you >>> 




_________________________________________________________________________ 
NV-L List information and Archives: http://www.tkg.com/nv-l
<http://www.tkg.com/nv-l>

Regarding to the loopback masks I absolutely agree with you. But...something must have changed from 5.1.2 to 6.0 in the way netmon discovers loopback interfaces since the "old" netview had no problems with them.

 

While trying around I finally discovered the device correctly (put the loopback address into the seedfile) and after 2 or 3 trys it finally got discovered. If as an alternative put a Lan-ip-address in the seedfile the device gets discovered without the loopback interface. Even better, there is no "loopback" object at all in the database.

 

Leslie pointed out that it could be related to the location.conf file and entries in the nettl.log. Next week I'll do more investigation on that topic

 

With kind regards / mit freundlichen Gruessen
Andreas Kuffer (System Manager UNIX and Enterprise Management)

-----Original Message-----
From: Sean Davidson [mailto:sean.davidson@mail.publix.com]
Sent: Freitag, Juli 07, 2000 16:38
To: 'IBM NetView Discussion'
Subject: RE: [NV-L] What happened to netmon Flag?

The loopback interface on a Cisco router and the loopback interface on a standard TCP/IP machine (127.0.0.1) are two different things. The loopback on a standard TCP/IP machine is typically used for communication between processes on that machine. So a 255.255.255.255 mask is valid.

 

The loopback interface on a Cisco router is a software interface that only drops when it is either intentionally shutdown or the router loses power. Other than that, it is a just like any other interface on the router. You have to give it a valid IP address with a valid subnet mask. 255.255.255.255 (network of all 1's) is never a valid TCP/IP subnet mask. There are no bits left over for hosts. The loopback interface on the cisco router is typically used to tie Cisco processes like DLSW,RSRB,BSTUN,STUN,etc...

 

If you have a primary and backup link on a router and you tie any of those processes to a real physical interface, that process no longer functions when the primary interface goes down and the backup link recovers the connectivity. This is where the Cisco loopback interface is useful. It is always up.

 

I don't believe the -L netmon flag you mention is the problem. Check the MIB2 interface table reported by the router and see if the loopback interface is there.

__________________________
Thanks,
Sean Davidson

Sr. Network Systems Engineer
Publix Super Markets, Inc.
P.O. Box 32015
Lakeland, Fl. 33802-2015
Email - sean.davidson@publix.com
Voice - (863) 686-8754 x6889
Fax - (863)616-5895

 

 

-----Original Message-----
From: Kuffer Andreas [mailto:Andreas.Kuffer@kuoni.ch]
Sent: Friday, July 07, 2000 3:48 AM
To: 'IBM NetView Discussion'
Subject: RE: [NV-L] What happened to netmon Flag?

I checked the netmask of the loopback interface, it was indeed set to 255.255.255.252. I asked the network guys why and the answer was that in earlier times you were not allowed (unable) to set a mask of 255.255.255.255. So the "loopback-netmask"-design of our network is 255.255.255.252 due to historical reasons.

Anyway we reconfigured the Cisco 1600 to 255.255.255.255, did a demand poll and also a new discovery but received the same results as I posted before.

I will call support today but I'm still interested if there is anybody out there with NetView 6.0 discovering loopback interfaces.

With kind regards / mit freundlichen Gruessen
Andreas Kuffer (System Manager UNIX and Enterprise Management)

-----Original Message-----
From: lclark@us.ibm.com [mailto:lclark@us.ibm.com]
Sent: Donnerstag, Juli 06, 2000 16:30
To: IBM NetView Discussion
Subject: Re: [NV-L] What happened to netmon Flag?

The -L flag was dropped in V6 (made a no-op) because it was no longer
needed. This is because, according to the internal update I attended,
32-bit masks are now fully supported; 32-bit masks are generally used for
software loopback interfaces. The connection is not exactly clear to me,
but I have seen loopbacks discovered successfully in V6, whether the
loopback was the address specified in the seedfile or not. So by my
voodoo-problem-determination methodology, I would suggest checking
the mask on the loopback that is missing. If it is not 255.255.255.255,
make
it so. If it is already so, look for some other, more mundane discovery
problem, or  call Support with a trace of the discovery handy.

Cordially,

Leslie A. Clark
IBM Global Services - Systems Mgmt & Networking
Detroit

Kuffer Andreas <Andreas.Kuffer@kuoni.ch>@tkg.com on 07/06/2000 04:59:40 AM

Please respond to IBM NetView Discussion <nv-l@tkg.com>

Sent by:  owner-nv-l@tkg.com

To:   "'IBM NetView Discussion'" <nv-l@tkg.com>
cc:
Subject:  [NV-L] What happened to netmon Flag?

AIX  4.3.2, NV 5.1.2 and NV 6.0
in  version 6.0 of netview it seems that one flag of netmon (-L, discover
loopback  interfaces with other address than 127.0.0.0) was withdrawn.

I have  a Cisco 1600 with loopback interface 10.10.224.85 and three other
interfaces

Demand  poll with NV 5.1.2 (netmon runs with -L):
Interface 10.10.232.86 (currently up)     responded to ping

Interface 10.10.21.1 (currently up)    responded to ping
Interface 10.10.224.85 (currently up)    responded to ping
Interface 10.10.240.86 (down since 07/03/00)    ping timed  out

Demand  poll with NV 6.0 shows:
Interface 10.10.232.86 (currently up)     responded to ping

Interface 10.10.21.1 (currently up)    responded to ping

Interface 10.10.240.86 (down since 07/03/00)    ping timed  out

So it looks like  netmon V6.0 doesn't discover the loopback interface I'd
like to see. Does that  work as designed? Did I miss anything? Can I use an
undocumented "-L  feature"?

Any help  is very welcome...Andreas

With kind regards / mit freundlichen  Gruessen
Andreas Kuffer  (System Manager UNIX and Enterprise  Management)

Kuoni Travel Ltd.
Dep. TOU
Neue Hard 7
CH-8010 Zuerich
Switzerland
Telefon : + 41 1 277 52 41
Fax     : + 41 1 272 52 55

<<< the smile that you send out  returns to you >>>

_________________________________________________________________________
NV-L List information and Archives: http://www.tkg.com/nv-l