So I'm currently running a Cisco router as DHCP server. On my corporate 
HQ network, I have two different "internal" subnets - 192.168.16.0 
(Corporate HQ computers), and 192.168.0.0 (Computer room stuff). The 
NetBSD box I have is running NAT, and sits at 192.168.0.1. The Cisco 
router sits at 192.168.0.250 and 192.168.16.1, and passes data back & 
forth. The trick is, both subnets are on the same physical network. For 
the Cisco, I just have it assign numbers from the 16.0 pool, and this 
works. Will this work on NetBSD's DHCPd? I've got something along these 
lines:

subnet 192.168.0.0 {
}

subnet 192.168.16.0 {
    range 192.168.16.129 192.168.16.254;
    option routers 192.168.0.1;
}

Will this tell DHCPd to assign .16 addresses, even though it doesn't 
have a .16 address itself? Or do I have to change it so that the NetBSD 
machine is routing packets between the .0 and .16 subnets, and the Cisco 
is not?

Also, does anyone have experience using 'Helper' dhcp forwarding on 
cisco routers? I have two dozen branches on the other side of that 
router, with various 192.168.x.0/24 subnets, and would like to have the 
one NetBSD box provide DHCP for all of them ('cause Cisco doesn't 
support DDNS updating). I >think< I know how it's supposed to work, but 
if someone's done it, I could use a nudge in the right direction.