[K12OSN] 2 DHCP Servers

Terrell Prude', Jr. microman at cmosnetworks.com
Mon May 17 11:34:08 UTC 2004

But then we've got to make sure that the standalone workstations 
(Windows, Mac, whatever) don't respond to the K12LTSP server's DHCP 
server. That's the bigger problem. The K12LTSP clients may not respond 
to the pre-existing (Windows-based) DHCP server, but the existing LAN 
workstations will happily respond to the K12LTSP server's DHCP server, 
and that can cause major problems without involving the IT staff of the 

Also, there may or may not be other issues of policy preventing more 
than one DHCP server on the LAN. I know there is in my district.


Dan Bo wrote:

>OK, ,I held off talking because I was sure that
>someone would mentione this, but why not use the VCI
>switch on Romomatic?:
> 	Require an encapsulated Vendor Class Identifier of
>"Etherboot" in the DHCP reply Requires DHCP support.
>Enabling this makes the boot ROM require a Vendor
>Class Identifier of "Etherboot" in the Vendor
>Encapsulated Options This can be used to reject
>replies from servers other than the one we want to
>give out addresses to us, but it will prevent
>Etherboot from getting an IP lease until you have
>configured DHCPD correctly.'
>You can operate two DHCP servers on the same port, but
>the Etherbooted computer will only respond to the one
>that specifies that it is for Etherboot. No messy
>setup.  No recompiling.
>>That would mean he's still using the K12LTSP DHCP
>>server, though.  
>>Personally, I would consider this a major
>>improvement over the Windows 
>>DHCP server, but he may have Layer 8 issues getting
>>in his way.
>>However, I know from experience that, running on a
>>386-33 w/ 32MB DRAM, 
>>ISC DHCPD can easily--EASILY--handle a large (1,000+
>>computers) high 
>>school.  We did just this at several schools back in
>>the Red Hat Linux 
>>5.2 days w/ nary a hiccup.  That was actually part
>>of the justification 
>>to get DHCP off the Windows servers.  :-)

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