Diff client IDs -> multiple leases

Jesse Saletan dhcp at saletan.com
Sun Mar 12 16:47:59 UTC 2006

I run a lab of about 250 systems and have been using ISC's DHCP ever since 
I replaced the MS DHCP server set up by my predecessor.  It's been working 
beautifully, but now I find myself coming up against a problem that has 
been discussed on this list before.

There are a number of systems on my network that multiboot between Windows 
and Linux.  When a Windows system requests a lease it sends its MAC 
address as the client ID.  When that same system is rebooted into linux 
the DHCP client does not send a client ID, and it is therefore issued a 
new lease with a different IP address.  I would like to limit clients 
to a single lease and IP address.

Back in 2004/2005 a guy named Didi posted some patches to change the way 
the dhcp server handles client IDs in order to address this problem.  Some 
discussion followed about whether it was proper to violate the the RFC to 
produce the desired result, and it was proposed that an option be added to 
dhcpd.conf to control this behavior, with appropriate warnings that it was 
not RFC compliant.

Can anyone bring me up to date on the status of this issue?  Does the 
current dhcp server include any option for how to handle client IDs?  Or 
is there some other way to produce the desired result, other than 
modifying all the dhcp clients' settings?


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