DHCP for multiple networks with static and dynamic assignments

Glenn Satchell Glenn.Satchell at uniq.com.au
Fri Mar 2 13:50:14 UTC 2007

>Date: Fri, 2 Mar 2007 14:00:56 +0100 (CET)
>From: "Wojciech 'Wheart' Penar" <wheart at lab103.ict.pwr.wroc.pl>
>To: dhcp-users at isc.org
>Subject: DHCP for multiple networks with static and dynamic assignments
>I'm operating network splitted into few physical networks (sometimes 
>containing several logical subnets). There are two DHCP servers working
>in fail-over configuration.
>Log looks like:
>Mar  2 13:56:52 server dhcpd: DHCPDISCOVER from 00:16:36:70:f2:34 via 
>x.y.z.254: network net_big: no free leases
>I'm using ISC DHCPD versions 3.0.1 and 3.0.4 (both linux).

You definitely need to use the same version on both hosts in a failover
pair. There are many bug fixes between the two version listed above and
reliable operation cannot be guaranteed. I would suggest the 3.0.1 is
upgraded to 3.0.4 to match the other host.

Then see if you still get errors.

Generally what you want to do should "just work". Make sure the host
definitions are in the global scope, that is outside any subnet or
shared_network declaration.

Also with your log, it is hard to diagnose what the error message might
be without knowing what x.y.z and x.x.x might be. It would be much
easier to diagnose with real IP addresses in there. If you must
disguise your addresses, then replace the first number with, say, 10.

One other thing - make sure all the shared_network statements only
contain subnets that share the same physical networks. Shared netwrok
means the server can assign an address from any subnet within the
shared network.

More information about the dhcp-users mailing list