Lookiing for FreeBSD DHCP Server Configuration example for handling remote segements

[Glenn Satchell]

>Date: Fri, 27 Jul 2007 15:23:37 -0400
>From: Dan Watts <dwatts at g4.net>
>To: dhcp-users at isc.org
>Subject: Lookiing for FreeBSD DHCP Server Configuration example for handling 
remote segements
>
>I'm setting up a DHCP server that needs to handle the DHCP requests for 
>various remote network segments. I don't want to have the DHCP server 
>key off the MAC address of the clients because the client MACs will 
>change too frequently. Because of this, I'm using the Option 82 setting 
>from the remote segment router to relay the DHCP requests to my central 
>server.
>
>I see the DHCP requests being sent to the DHCP server but the server 
>generates the following error message:
>
>DHCPDISCOVER from 00:00:39:86:0d:a7 via 10.100.52.1: unknown network segment
>
>The IP address 10.100.52.1 is an IP address of the router that is acting 
>as a Helper Agent.
>
>I've been reading the man pages and using Google, but so far have not 
>been able to find any examples for this type of configuration. I have 
>found some references to this as a way that Cable ISPs would configure 
>the DHCP server for their clients but none have examples.
>
>Any help in locating an example configuration would be greatly appreciated.
>
>Dan
>
>
There's no separate documentation for remote network segments and local
network segments because you configure them identically in dhcpd.conf.

In this case you'll have a subnet declaration for the local network.
You need to add one for the network containing 10.100.52.1. Possibly
something like this:

subnet 10.100.52.0 netmask 255.255.255.0 {
  option touters 10.100.52.1;
  range 10.100.52.20 10.100.52.99;
  other options for this subnet...
}

You must describe your network accurately as far as network numbers and
subnet masks go.

dhcpd decodes the subnet required by looking at the gateway address
(10.100.52.1 in this case) and finding the subnet definition it belongs
to. It then applies those pool or subnet defintions, then and global
definitions.

regards,
-glenn