RE: [nv-l] Managing routers with duplicated IP address

["Evans, Bill" <Bill.Evans@hq.doe.gov>]

You should take a look at the archives at http://lists.skills-1st.co.uk/mharc/html/nv-l/ . There you will see some discussions on duplicate entries.  It's not a good idea.  Some have used the HSRP marking of the interfaces in the netmon.seed file as a partial solution.  If half the Interfaces are marked as administratively down it may also help since NetView tends to ignore AD interfaces. 

 

I still prefer to see the switching done at a decent level 3 and be visible to the world.  If you switch interfaces at level 2 you never know what the network map really looks like.  Cisco HSRP was created to do just that kind of visible Level 3 backup switching (Hot Standby Routing Protocol).  When the backup is activated the interface and its connector to the network move on the NetView map to show the proper topology. 

 

Good luck with it.

 

Bill Evans
Tivoli NetView Support for DOE
301-903-0057

-----Original Message-----
From: Marcos Antonio Pezzutti Filho [mailto:pezzutti@banespa.com.br]
Sent: Thursday, April 22, 2004 4:55 PM
To: 'nv-l@lists.us.ibm.com'
Subject: RE: [nv-l] Managing routers with duplicated IP address

Bill,

 

In our network threre are some routers with the same IP address on its interfaces.

It was the way the the net guys have found to implement a backup circuit.

The switch between both interface is done by level 2 (in our case a frame-relay switch).

 

Eg.

Router 1:

Eth0 (primary interface): 172.27.1.1

ser0: 10.1.1.1

ser1: 10.2.1.1

ser2: 10.3.1.1

 

Router 2:

Eth0 (primary interface): 172.27.2.1

ser0: 10.1.1.1

ser1: 10.2.2.1

ser2: 10.3.1.1

 

In this case both routers have 2 IP duplicated.

 

There is no HSRP or VRRP set.

 

How can I configure Netview to modelate both routers ?

 

Thanks

 

Marcos Pezzutti

-----Original Message-----
From: Evans, Bill [mailto:Bill.Evans@hq.doe.gov]
Sent: Thursday, April 22, 2004 5:33 PM
To: 'nv-l@lists.us.ibm.com'
Subject: RE: [nv-l] Managing routers with duplicated IP address

Yes, it's possible.  It's absolute necessary with the HSRP support. This is from /usr/OV/conf/netmon.seed.

#    Hot Standby Routing Protocol (HSRP) Support
#
#      HSRP interfaces may be specified here for netmon to acknowledge them.
#      Only the public IP address need be entered. 
#
#      Use the prefix '%', and use the same syntax for ranges and wildcards
#      described above for positive seed entries.  For instance, if 1.1.1.1
#      is the IP address of the HSRP interface that switches between two
#      routers, enter,
#
#         %1.1.1.1

Other reasons may exist for doing so and NV can handle accidental duplicate interface adddresses on routers but it doesn't like it.  It definitely won't handle routers whose primary interface addresses are duplicated; as you've seen it will delete one of them.  To give you a better answer we need to know why there are duplicate addresses.  The solution may be to use CNAT  or it may be to identify the devices as HSRP or it may be simply to clean up your network interface definitions.

If you search the archives for this mailing list you will see a few cases where the HSRP support is used to handle duplicate IF addresses present for other reasons.  

You simply haven't given enough information for anyone to send an intelligent answer.  Why do your routers have duplicate addresses? 

Bill Evans
Tivoli NetView Support for DOE
301-903-0057

-----Original Message-----
From: Marcos Antonio Pezzutti Filho [mailto:pezzutti@banespa.com.br]
Sent: Thursday, April 22, 2004 3:58 PM
To: 'nv-l@lists.tivoli.com'
Subject: [nv-l] Managing routers with duplicated IP address

Dear friends,

Our Environment:

AIX 4.3.3 ML-10
Tivoli Netview 7.1.4
Tivoli Framework 3.7.1
ITEC 3.9

We´d like to know if it´s possible to manage a router with an IP address duplicated on another router ?

Thanks in advance

Marcos Antonio Pezzutti Filho
Santander Banespa - Infra-Multiplataforma
* Fone: 5854-6339 * Fax: 5538-5260
pezzutti@banespa.com.br <mailto:pezzutti@banespa.com.br>