I'm currently travelling and without access to my network of multiple 2700's.
On the slave, make sure your TURN OFF DHCP and select an IP within the range of the primary and when you set the secondary copy the subnet of the primary.
Hi Yandoo. If router LAN IP is 192.168.1.254, just set the subnet mask to 255.255.255.0.
Your hosts IP range should be 192.168.1.1-253. That's as basic as you can get. Good luck.