OUCH. You're on a delimma with this issue; DHCP in one environment and Static in another.
First, ip addresses is not a good identifier; your router should be able to track the MAC addresses which is precise.
Second, regardless of the solution, you have a major security exposure where a device moves from work, to home and back again.
Windows 7 NAP service addresses this concern. You should make every effort to get NAP services operational for every laptop that you allow onto your network.
You must consider the needs for File/Print sharing for the following:
All
desktop systems should connect to router-A.
All
laptops must connect to another router-B and you wire
Code:
Gateway---Router-A-----Router-B(wifi)
| |
| +- - - ALL wifi connections
|
+-- all desktop systems
If the DHCP on router A is servicing 192.168.1.1->255
then router B
- should serve 192.168.2.1->255,
- use DHCP for all laptops
- AND allow only known MAC addresses (as well as use encryption).
your demand to register all laptops is your security and the above enforces that choice.
Router-A is immune from the complexity and only needs a persistent route as follows
The connection between routers will cause the WAN port on router-B to have an address belonging to
router-A - - this should be a fixed IP address (eg 192.168.1.253)
Now you add a persistent route to router-A
- route 192.168.2.0 -> 192.168.1.253