address range ... not on net

[Stuart Kendrick]

i have multiple subnets defined on a particular network. the giaddr sits 
on one subnet; and the pool from which i want to hand out DHCP addresses 
sits on another

          10.10.42.1
router --------------------------------- switch ---------- DHCP clients
          10.10.88.1

the router supports both 10.10.42.0/24 and 10.10.88.0/24 on this 
network.  the bootp relay agent (router) is setting giaddr to 10.10.42.1 
... but i want to hand-out DHCP addresses from 10.10.88.0/24


shared-network test {
        subnet 10.10.42.0 netmask 255.255.255.0 {
        pool {
                 range 10.10.88.1 140.107.88.254;
        }
        option subnet-mask 255.255.255.0;
        option broadcast-address 10.10.88.255;
        option routers 10.10.88.1;
        }
}


when i load dhcpd with this config file, i see the following in syslog:

Jun 30 07:36:25 guru dhcpd: Address range 10.10.88.1 to 10.10.88.254 not
 on net 10.10.42.0/255.255.255.0!


now, i would agree with that log message ... but i don't see this as a 
problem.  in addition, the protocol specification doesn't see this as a 
problem

from RFC-2131:

   Note that, in some network architectures (e.g., internets with more
   than one IP subnet assigned to a physical network segment), it may be
   the case that the DHCP client should be assigned an address from a
   different subnet than the address recorded in 'giaddr'.  Thus, DHCP
   does not require that the client be assigned as address from the
   subnet in 'giaddr'.  A server is free to choose some other subnet,
   and it is beyond the scope of the DHCP specification to describe ways
   in which the assigned IP address might be chosen.


however, perhaps ISC DHCPd sees this as a problem, i.e. doesn't support 
this capability

insights?

--sk

stuart kendrick
fhcrc