No, nslookup will not go back and check /etc/hosts. That is DNS only. The
'host' command will check both sources, in the order defined in
/etc/netsvc.conf
(if on AIX). I would fiddle with that to control the test environment. For
example:
/etc/netsvc.conf contains: hosts=local,bind
means first the /etc/hosts file, then dns - all servers
/etc/netsvc.conf contains: hosts=local
means only chech the hosts file, and ignore DNS even if /etc/resolv.conf
exists
/etc/netsvc.conf contains: hosts=bind
means ignore the hosts file.
Then you can just use the 'host' command to test with.
Take care with this. If you inadvertently cause the name of your server to
change
(eg it is not the same in both places, in all directions), you will have
trouble with
Framework and Netview.
Other operating systems have ways to switch this order, I just don't know
what
they are. The sysadmin will, if you have one.
Also, there was a really exciting set of postings on the cost of very large
/etc/hosts files right on this listserver around June 15th. Go to the
archives
at www.tkg.com/nv-l and check them out.
Cordially,
Leslie A. Clark
IBM Global Services - Systems Mgmt & Networking
(248) 552-4968 Voicemail, Fax, Pager
William.Stringfellow@bankofamerica.com@tkg.com on 10/13/2000 06:11:14 PM
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] Hostname Resolution
We are looking at whether or not using /etc/hosts for name resolution is
impacting performance. We currently have >33K interfaces in our host file.
I only find reference to hostname resolution in the NetView Release
Notes,
section 9.9. In that section it states "If no nameserver is used, then the
resolve subroutines use the /etc/hosts file for network address
resolution.".
It than recommends that you do an nslookup to check repsonse time.
Since I
am using /etc/hosts I get:
<root@nv6ksfo03:/etc> nslookup nv6ksfo03
Server: nv6ksfo03
Address: 0.0.0.0
*** nv6ksfo03 can't find nv6ksfo03:No response from server
And the server just sits there until it times out. The hostname used
is in
the /etc/hosts file, and no it doesn't matter that I am looking up the
NetView
box on itself, it's still in the hostfile and the results don't change if I
look
for another device.
Questions:
1. Should the nslookup work using /etc/hosts, or is /etc/hosts only used
by
NetView for it's internal routines?
2. If this process doesn't work using /etc/hosts, how can I compare
performance
between using it and using a name server?
Looking forward to the response,
Bill Stringfellow
Bank of America Network Management Systems Group
Concord, CA
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