[K12OSN] LTSP Setup question.

"Terrell Prudé, Jr." microman at cmosnetworks.com
Fri Oct 15 23:27:44 UTC 2004

Martin Woolley wrote:

>On Thu, 14 Oct 2004, Brad Bendily wrote:
>>I want my server to be setup with only 1 NIC and I'd like the
>>workstations to remain on the public LAN.
>>So I guess this means I would have to have my already existing DHCP
>>server hand out the location of the LTSP tftp server?
>Why not run two DHCP servers, your existing one and the LTSP server?   We have 
>8 DHCP servers, the 6 LTSP servers and 1 NT which all dole out the same IP 
>range (for the students), and a W2K which doles out a different range (for 
>the admin staff).   The students run a mix of ltsp and win 98 and the admin 
>staff XP. Not only does this never cause problems (perhaps we are lucky) but 
>I have done a huge amount of investigation on our network, and the thin 
>clients always pick up an ip address from a random choice of one of the Linux 
>boxes and the W98 clients (to the NT server) generally get theirs from said 
>NT box.  If they get one from one of the Linux boxes then they still can 
>connect to the NT box.  The  XP boxes always get theirs from the W2K box.  
>Like the ad says "isn't in nice when things just work"

You're very lucky indeed, unless you're running your K12LTSP servers in 
the "standard" 2-NIC architecture.  Having eight DHCP servers serving 
the same broadcast domain can be very, very dangerous.  Yes, I know some 
on this list have done this and haven't run into problems, or they run 
them on nonstandard UDP ports, but unless you know what you're doing, 
and you have a specific, i. e. very weird, situation you need to solve 
in this way, I would strongly recommend against this practice.  I've 
been burned way too many times with multiple DHCP servers serving the 
same broadcast domain; it's taken out several LANs in my schools.

So, if you're in a single-NIC K12LTSP setup, don't do it.  If you're in 
a dual-NIC K12LTSP setup, though, you should be fine.

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