Ref: 03250314
Title: How to Manage a Name Server Failure
Date: 7/7/88

Copyright 3Com Corporation, 1991.  All rights reserved.

PROBLEM:  If I have a network with 10 servers and 1 Name server,
my Name server goes down, and I immediately bring up a Name
server with the same net # and the same NS_DOM.XXX files, what
happens to the users who are still logged in?  (Just fine or big
problems?).

Then, when our original Name server is fixed, what procedure do I
use to bring it back online?  What would happen if both Name
servers were online for a few minutes before the backup server
was shut down?

Is there a way to make both servers have the same Ethernet
address?  Is this a good idea?

SOLUTION:  None of the users who are already logged in will
notice the change UNLESS they attempt to do something requiring
Name service access, such as linking to a server that is not
their default server or SENDING A MAIL MESSAGE.

A user who requires Name service access will see a "Name Server
not responding ..." message.  That user, to recover, would then
have to login again to load the new Name service address.

Any user who logged in while the backup server was online will
have to log back in to the original Name server once it is
rebooted in order to access the Name service facilities.

When two Name servers (with different addresses) are on the same
network, the one available at the time will respond to Name
service requests--the server selected is arbitrary and beyond the
user's control.  Therefore, when on a second attempt is made to
access the Name service and the alternate server tries to
respond, the user would see "Name Server not Responding."

Re having the same Ethernet address...don't.  Two servers with
the same Ethernet address cannot be online in the same network.
