NIS Slave can't be auto-discovered

[Ian Melnick <dazed@vonsteuben.cps.k12.il.us>]

Hello, all

I set up a NIS master a while ago, for use with a small network. Since
then it's grown, and I found a need for a NIS slave for times that the
master has gone down due to hardware upgrades, etc.

So I set up the slave, and it seems to work right. Clients switch to it
when NIS is no longer available from the master. However: this switching
only works when I specify both servers in the /etc/yp.conf on the
client machines. Before, I didn't need to specify anything in
/etc/yp.conf. I used to have to specify the master, but then one day did
something so that it wasn't required anymore (either that or it was a
feature that I hadn't noticed previously or something). So that saved me
typing the master server's IP into all the yp.conf files on the clients.

Anyway, I was wondering what that "thing" was, so that I could configure
the slave server the same way so that reconfiguration of the clients
wasn't necessary, and they'd auto-discover the slave when the master
wasn't available.

Thanks!
/ian.