Serving addresses to multiple subnets

[John Tabasz (jtabasz)]

Thanks Tom, I'll give it a try.

John

-----Original Message-----
From: dhcp-users-bounces at lists.isc.org [mailto:dhcp-users-bounces at lists.isc.org] On Behalf Of Paine, Thomas Asa
Sent: Wednesday, October 07, 2009 2:46 PM
To: Users of ISC DHCP
Subject: RE: Serving addresses to multiple subnets

John,
	The Cisco router will not generate two relay requests, only one, and only for the primary address.  That said, however, you CAN use a shared network statement to wrap those two subnet statements together.  I think it will serve out the highest addresses first, but nonetheless I think it will do what you need.

Like this...

shared-network Foobar{
   subnet 10.1.100.0 netmask 255.255.252.0 {
   option routers 10.1.100.1;
     option subnet-mask 255.255.252.0;
     option domain-name-servers x.x.x.x;
     option domain-name "mydomain.com";
   deny unknown-clients;
   } 


   subnet 10.1.200.0 netmask 255.255.254.0 {
   option routers 10.1.200.1;
     option subnet-mask 255.255.254.0;
     option domain-name-servers x.x.x.x;
     option domain-name "mydomain.com";
   deny unknown-clients;
   }
}

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
   Thomas Paine (paineta at uwec.edu)
   University of Wisconsin - Eau Claire
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

From: dhcp-users-bounces at lists.isc.org [mailto:dhcp-users-bounces at lists.isc.org] On Behalf Of John Tabasz (jtabasz)
Sent: Wednesday, October 07, 2009 3:49 PM
To: Users of ISC DHCP
Subject: Serving addresses to multiple subnets

Hi,

I have a Cisco router with a secondary interface on one of the physical interfaces, e.g. 

Int fa0
   Ip address 10.1.100.0 netmask 255.255.255.0
   Ip address 10.1.200.0 netmask 255.255.255.0 secondary

My dhcp server is sending addresses to the primary subnet, but not to the secondary subnet.
There are subnet declarations for both subnets:

subnet 10.1.100.0 netmask 255.255.252.0 {
option routers 10.1.100.1;
  option subnet-mask 255.255.252.0;
  option domain-name-servers x.x.x.x;
  option domain-name "mydomain.com";
deny unknown-clients;
} 


subnet 10.1.200.0 netmask 255.255.254.0 {
option routers 10.1.200.1;
  option subnet-mask 255.255.254.0;
  option domain-name-servers x.x.x.x;
  option domain-name "mydomain.com";
deny unknown-clients;
}

And fixed address declarations for each of the hosts I want to serve addresses to. 
I can see the requests hitting the interface on my dhcp server via snoop, but no response is forthcoming. 

Any ideas?

Thanks,

John

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