DHCP server sometimes not found

Rippl, Steve rippls at woodlandschools.org
Mon Dec 15 04:02:54 GMT 2008

We found exactly the same thing.  We took dhcp off the ltsp server and
put it on a separate box (a low power P4) and suddenly were able to boot
30 clients at the same time (with ltsp5).

It seems that ltsp5 hammers the dhcp server (at least from Ubuntu,
that's all we've tested so far), I think if you watch the logs you find
the clients querying the dhcp server over and over again.  We figured
that as the box got busy serving up the tftp kernels the dhcp would
start to fail/timeout.

For this and other reasons (Active Directory authentication hammering
the server too, general slowness) we went back to ltsp4 (on Debian) and
things are working much better there in general, it's much faster!

Steve Rippl
Woodland School District.

From: edubuntu-users-bounces at lists.ubuntu.com
[mailto:edubuntu-users-bounces at lists.ubuntu.com] On Behalf Of Sergio
Sent: Sunday, December 14, 2008 2:28 PM
To: edubuntu-users at lists.ubuntu.com
Subject: DHCP server sometimes not found


I'm finishing our new computer room with 12 thin clients and a 8.041
Edubuntu server. Everything seemed fine on the first clients I tested,
but I just found I can start no more than 4 or 5 at the same time.
The other ones just wait for a DHCP to give them a valid IP address, and
there's no way to obtain it.
I checked cabling and switch, but it's just a matter of who come first:
the first 4 (or 5) clients just get their IP, the other ones don't.
Consider that in my /etc/ltsp/dhcpd.conf I put the correct MAC addresses
to assign fixed IPs, and they work fine for the first clients starting.

Looks like somebody had the same problem, while everything worked fine
in 7.10 with LTSP 4.2:

Any suggestion ?
It's the last obstacle to get our only computer room working ...


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