Subject: netbooting across two switches
To: None <>
From: Jan Schaumann <>
List: tech-net
Date: 02/21/2006 17:18:21
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This is somewhat OT, since it's not strictly a NetBSD issue, but I
figured maybe somebody here can help me out anyway.  And all machines
involved are actually NetBSD machines, so there. :-)

I have the following setup:

A number of cluster nodes ('node's) are connected to an extreme networks
switch ('Summit'), netbooting off a fileserver ('doppelbock') connected
to the same switch.  So far so good.  I now have added a number of new
nodes ('NNode's), but since the Summit switch is full, I connected the
Summit switch to a Cisco Catalyst 4506 ('cat4506'), to which the NNodes
are connected.  cat4506 has three vlans.

This looks like so:

[ node ]+                                           +[ NNode ]
[ node ]+                                           +[ NNode ]
[ node ]+----- [ Summit ] ------- [ cat4506 ] ------+[ NNode ]
[ node ]+          |                                +[ NNode ]
[ node ]+          |                                +[ NNode ]
             [ doppelbock ]

Summit has all nodes on one vlan, cat4506 has all NNodes on one vlan,
and the connection between the two switches is on the same vlan, as is
the connection to doppelbock.

The nodes can netboot off doppelbock just fine, but the NNodes can't.
They pxeboot and get the right IP address from doppelbock, they tftp the
kernel and all's well, but when the kernel tries to DHCP, it times out.

If I connect the NNode directly to the Summit, then they netboot fine,
too.  So it's obviously a matter of configuring both switches correctly,
but I'm not sure what exactly needs to be done.

I've tried to configure 'ip helper address' on cat4506 and made sure to
'enable bootprelay' on the Summit, but I have to admit I'm just guessing
here.  So if somebody has done this and could suggest to me the
necessary settings that I seem to be missing, I'd appreciate it.


I always said there was something fundamentally wrong with the universe.

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