Our DNS only has the loopback for forward
and reverse lookup. Only NetView seems to be interested in the interface
addresses. To make NetView work I have all the IP addresses in the
/etc/hosts file to allow reverse lookup to work. They all resolve
to the same name. The primary entry is the loopback address. The magic
sequence used by NetView is essentially to take the interface address and do GetHostbyAddr
to get the hostname then do a GetHostbyName to get the IP address of the loopback
interface. (I'm not a Unix programmer but I think that's the
order and names of the calls.)
To maintain the hosts file I have a script
which does an SNMPWALK on the MIB II IP Address table on each router to make
sure which interfaces are there then create a hosts file from the
addresses. If the Router gurus remember they tell me when they make
changes but they don't always remember. It's part of periodic
maintenance and troubleshooting. At least it's under my control and
I don't have to wait for a DNS update request to be handled.
As to the seed file, I believe you can do
what you describe. The problem comes when you do both positive and
negative ranges which overlap. Or any ranges which overlap. As always,
when a question like this arises, try it. That's why teaching the
NV for Admin class was a bear; when such a question was asked I had to try things
like this in the evening so I could answer the question the next morning.
Bill
-----Original Message-----
From: CMazon@commercebankfl.com
[mailto:CMazon@commercebankfl.com]
Sent: Monday, March 08, 2004 3:46
PM
To: nv-l@lists.us.ibm.com
Subject: RE: [nv-l] seed file
Bill,
You
said you only have the loopback address in DNS, is that true for reverse lookup
as well? or do you list all the ip addresses in reverse-lookup with one name. This
is the present scenario that i am working with.
A
seperate question on the seed file... can you list a range of ip addresses
(Servers mainly) and then list negated single entries within that range or vice
versa? or is this also too much work for netmon?
Carlos
|
|
"Evans, Bill"
<Bill.Evans@hq.doe.gov>
Sent
by: owner-nv-l@lists.us.ibm.com
03/08/2004 03:21 PM
Please
respond to nv-l
|
To: "'nv-l@lists.us.ibm.com'"
<nv-l@lists.us.ibm.com>
cc:
Subject: RE: [nv-l] seed file
|
Another important
item is to use only one name in DNS for each router. All the interfaces
on that device should resolve to the same name. The name should resolve
to the loopback address for the router.
This gives you the best functioning of NetView
although there is a continuing argument from many who want a unique DNS name
for each interface for other reasons. I find the device name qualified by
the interface name (e.g. Router.Serial1/0) gives the uniqueness I need for
interfaces. When necessary I override the DNS with a local hosts file to
achieve this. In my present situation the DNS has only the loopback
address and I use hosts to resolve the other names.
Bill Evans
-----Original Message-----
From: Paul [mailto:pstroud@bellsouth.net]
Sent: Monday, March 08, 2004 2:05 PM
To: nv-l@lists.us.ibm.com
Subject: Re: [nv-l] seed file
Chris,
Only use one IP for each device, you are causing netmon to do a lot of
additional and unecessary cycles. Let me explain:
netmon reads the entries from the seedfile, pings the
node, if it
responds, it is added to the database and an SNMP poll in scheduled.
When the device is polled via SNMP all the interfaces are discovered
and finally the full device is added to the map.
If you put multiple IPs in the seedfile for the same
device it will be
added and polled mutliple times, one for each ip in the seedfile. This
is uneccesary as netmon will already discover it via SNMP. That and
you might confuse things. Ie. netmon discovers on interface and adds it
and finds another interface and adds it before the first SNMP poll
is completed. Now it must delete one of the devices(as we know they
are on the same device) and fixup the correct device. This is all
uneccesary processing.
The best practice is to add a single interface from
each device.
Paul
Christopher J Petrina wrote:
>
> Greetings all,
>
> UNIX netview. Using a seefile forl imited discovery. In the
seedfile
> I have multiple entries (multiple IP's) for the same device, ie(every
> ip interface of a single router) is in the seedfile. When netview
> runs through the seedfile it finds the first IP of a device when it
> comes to the second IP of that device what does netview do. Each IP
> interface also has an entryo in DNS as well. Does netview change the
> name of the device if it finds another name. Also once it has
> initially found it, and then polls the device (SNMP) what name will it
> chose for the device in netview, and why does it sometimes change the
> name of the device.
>
>
> Chris Petrina