Routing with DHCP
If you want to allocate IPs from DHCP and need to access multiple networks then you need to setup routes. This is tricky with DHCPD as it's not a default (documented) option.
options static-routes doesn't work as it only routes 1 ip (not a whole network).
So, add this to your dhcpd.conf global section:
option classless-routes code 121 = array of unsigned integer 8;
Then in your subnet/host/whatever section put:
option classless-routes 24,192,168,0,192,168,0,254
What's with all that numbers? That doesn't look normal. Sure, it's some compact way of doing things.
The 24 is the "significant bit" lark for your subnet. So 255.255.255.0 = 24. The next bit is your host mask. In this example 192.168.0 (there is no last octet, no point). Then there is the router you want to use, in this example 192.168.0.254.
This will not work with old OSes.