SUMMARY : netmask

From: Jaap Romers (
Date: Tue May 26 1992 - 03:42:38 CDT

Last week, I posted a message, where I asked for help with NIS-problems
on a subnet with a netmask.
Here's a part of my original message:

> The Network-group decided to use a netmask in the
> subnetted network. After the change of netmasks and IP-numbers
> almost everything worked O.K., except NIS on the diskless Sun's.
> We changed the netmask in the local /etc/netmask and the NIS netmask-map and
> in /etc/rc.local on the diskless client we configured ifconfig as follow:
> ifconfig -a netmask + > /dev/null
> ifconfig le0 broadcast > /dev/null
> During the clients boottime we get a "NIS server not responding for domain..",
> after ypbind is started in /etc/rc.local.

Some people asked if I had a NIS-server on the subnet, because broadcasts
are generally not forwarded by routers. Well, we have a NIS-server on the
subnet, so that was not the problem.

Another response said that we should have 0-broadcasts. If you only have
Sun's on your subnet, it is probably OK to use 0-broadcasts. But we
have a heterogene network, so we must have 1-broadcasts.

Kevin Elphinstone ( suggested the following:

> The problem was solved by giving all the diskless clients a hostname.le0
> file just like on the diskfull machines. /etc/rc.boot looks for this
> particular file and runs ifconfig appropriately. It seems that if this
> initial ifconfig is not done, then changing the broadcast address later
> in rc.local breaks yp? I don't know why this is the case, this was just
> a quick fix I stumbled across.

We didn't try it, but I think it will work.

Stefan Turowski's <> answer was the
best, and it solved our problem:

> Did you check the routing tables after the ifconfig's ?
> What I found out, is that the Sun does not enter the correct entry for
> an interface in its routing tables.
> This in turn will cause all broadcast packets to be send to the default
> gateway and if this is not a Sun _and_ a NIS-Server the NIS binding fails.

This was exactly what happened. With a traffic-analyzer we observerd traffic
between the NIS-client and the Cisco-gateway.

> Solution:
> ifconfig -a netmask + broadcast + > /dev/null
> ifconfig le0 broadcast > /dev/null
> (the first ifconfig defines an incorrect broadcast address, but a
> correct routing table entry.)

I changed the /etc/rc.local and it worked.

Well folks, thanx again for the quick response.


        Ron Wessels <>
        Barry Margolin <barmar@Think.COM>
        Manfred Kwiatkowski <kwia4000@wncs.zrz.TU-Berlin.DE>
        Kevin Elphinstone <>
        Stefan Turowski <> (Siebren van der Zee)

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