I have 2 DHCP servers on the same subnet serving clients IP addreses. I've load RSD2 with the dhcp tick box enabled on the 2 servers. When clients get a DHCP IP they can get it from either DHCP server. I've noticed that some IP do not get detected as rogue and I think it might be due to the following.
From the logs it looks like you can only have one active rogue sensor per subnet, so one of the dhcp sensors is active and the other is passive - this might explain why only half the clients are detected. Is this how it works?
09-18-08 11:39:42,730  INFO RSDSensor <> - Created a virtual sensor for 10.4.13.0 on interface HP NC7771 Gigabit Server Adapter.
09-18-08 11:39:42,730  INFO RSDSensor <> - Virtual sensor 34268 initialized at network address: 10.1.0.0 on interface 'HP NC3163 Fast Ethernet NIC'
09-18-08 11:39:42,730  INFO RSDSensor <> - Virtual sensor 1824 initialized at network address: 10.4.13.0 on interface 'HP NC7771 Gigabit Server Adapter'
09-18-08 11:39:42,746  INFO Pipe <> - Pipe communication started on thread 28968 09-18-08 11:39:44,136  INFO RSDSensor.ServerCom <> - Sending data to the server at https://10.1.6.83:8444/rsdsensor/engine.sm