What about putting your router loopback interface addresses in a NetView
seed file?




From: Mark.Lucas AT ERCGROUP DOT COM on 11/10/98 10:13 AM


Please respond to NV-L AT UCSBVM.UCSB DOT EDU

To:   NV-L AT UCSBVM.UCSB DOT EDU
cc:
Client:
Subject:  How to get NV5.1 to recognize loopback addresses in routers




Joel,
I filed your below response away knowing at sometime I'd refer back to it.
I'm in the process of building a NV5.1 system and there are several Cisco
routers in our network that have multiple paths to them.  I was looking for
a way to associate one host name/IP address with a router such that via DNS
we'd always be able to telnet/ping/traceroute to that node and not have to
worry about a particular interface being down on a router.  Assigning a
loopback address to the router seems to be the way to go to achieve that
capability.
I pre-configured DNS as you recommended below.  That is, I assigned
loopback
addresses to all routers and only put those names in DNS.  However, as
Netview is discovering my network, it's mechanism is using the IP address
of
the first interface it encounters for a particular router as it's label,
selection name, and IP hostname, etc.  Furthermore, an "ovobjprint -s ..."
of that router doesn't even acknowledge the presence of the loopback
interface, as it's "TopM Interface Count" is 3 (two serial plus 1
token-ring).
So, my question to anybody out there is is there anyway that I can have
Netview recognize these loopback addresses?  And, furthermore, would there
be a way of telling or fooling  the discovery mechanism into picking the
loopback interface as it's main object in the database?  Thanks for any
suggestions.
Mark S. Lucas
Employers Reinsurance Corp.
Networking Systems Specialist
(913) 676-5718 (direct)
(913) 676-5108 (fax)
Mark.Lucas AT ercgroup DOT com
-----Original Message-----
From: Joel A. Gerber [mailto:joel.gerber AT USAA DOT COM]
Sent: Tuesday, August 25, 1998 7:53 AM
To: NV-L AT UCSBVM.UCSB DOT EDU
Subject: Re: NetView-T/EC-DNS Implementation Problem... HELP!

If your routers support it, I would recommend configuring a virtual
loopback
interface with an IP address, and then define that IP address in your DNS.
Make sure that it is the only IP address defined in your DNS to avoid the
problem with round-robin.  If there are multiple paths in your network, you
will also get the added benefit of better connectivity to your routers.
For
example, if you have multiple IP addresses defined in DNS, and one of them
is not accessible because the interface is down, (or the path to that
interface is "broken"), then NetView will fail trying to access that
router.
The round-robin support in DNS will help a little, because it will return
the next IP address the next time NetView queries that router.  However,
you
will still have failures.  Loopback interfaces solve this problem because
the routers will automatically update their routing tables to provide a
path
to the loopback interface when an interface is down (assuming there IS
another network path).

        -----Original Message-----
        From:   Julio W. Troya [SMTP:julio_troya AT HOTMAIL DOT COM]
        Sent:   Monday, August 24, 1998 15:50
        To:     NV-L AT UCSBVM.UCSB DOT EDU
        Subject:        NetView-T/EC-DNS Implementation Problem... HELP!
        We are currently in the process of implementing DNS for our
        NetView environment and have found a problem which we
        cannot solve.
        Our environment consists of a NetView (5.0) server which feeds
        multiple interface-router events to T/EC (3.1), and here's where
the
        problem manifests itself.  Both servers are running with AIX 4.2.
        Our NetView server is also configured as a secondary DNS server,
and
        whenever NetView resolves the host name to an IP address, it will
        always return with a different primary IP address for the router.
        It seems that it is selecting the next IP address in an
"round-robin"
        fashion.
        Because we get a different IP address for each event, T/EC is
unable
to
        correlate clearing events with old down events.  For example, T/EC
        will receive a node down event:
              RG100BRA   10.0.7.131     Node down
        when the clearing event arrives, the interface address will be
        different, and
        hence T/EC thinks it is a different device:
              RG100BRA   10.22.0.2      Node up
        I have included the response to two nslookup commands, the second
        executed immediately after the first.  As you can see, for each
        command, we get a different IP address as the first interface in
the
        router.
             > nslookup RG100BRA
             Server:  localhost.bns
             Address:  127.0.0.1
             Name:    RG100BRA.corp.bns
             Addresses:  10.0.7.131, 10.22.0.2, 10.22.0.6, 10.170.0.1
                       10.171.0.1, 10.0.12.3, 10.0.4.189

             > nslookup RG100BRA
             Server:  localhost.bns
             Address:  127.0.0.1
             Name:    RG100BRA.corp.bns
             Addresses:  10.22.0.2, 10.22.0.6, 10.170.0.1, 10.171.0.1
                       10.0.12.3, 10.0.4.189, 10.0.7.131
        1. We would like to know if there is a way to 'force' NetView to
use
           a specific IP address as the primary IP address for the router,
           without having to use the /etc/hosts file?
        2. Has anyone implemented DNS, NetView and T/EC successfully?
        3. Is there a Redbook which describes this type of implementation?
        Any help will be greatly appreciated.


        Julio W. Troya
        Associate Technical Specialist
        Enterprise Systems Management
        Bank of Nova Scotia
        Scarborough, Ontario, Canada
        Tel: 416-701-7144
        Fax: 416-288-4400
        E-mail: julio_troya AT hotmail DOT com

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