DHCP requests from nodes w/ different subnet masks

[m vossberg <[e-mail]>]

I am looking for information on how DHCP handles a request from a client 
that is on a network that has a different subnet mask than the server.  The 
scenario would be a PC client on an ethernet network directly attached to a 
cisco router that uses a class b IP address with a mask of 255.255.255.240. 
The dhcp server (Sun Ultra running Solaris 2.5.1) is on different network, 
an ethernet directly connected to another cisco router with the same class 
b type address with a subnet mask of 255.255.255.192.  The two routers are 
connected via a demand dial link through the async lines.  The cisco router 
directly connected to the PC client has an "ip helper-address 
xxx.xxx.xxx.xxx" of the dhcp server on the other network.  This allows dhcp 
requests to be directed to the dhcp server.

As of yet, I have not been able to find any reference to this type of 
configuration/operation.  We have confirmed that request packets are 
traversing the routers correctly and getting to the dhcp server.  While 
running dhcpd in debug mode and using snoop we have seen the client 
requests, but the server does not respond.

Does "standard" DHCP provide for such a situation or is this up to the 
specific vendors to offer this "feature"?  If DHCP does indeed cover this 
scenario could you please point to the documentation/white papers that 
describe this operation.

thanks,
m vossberg