WE are looking to implement IDS in out network and I have some questions if I get 4250 can I span multiple network segments with the one interface it comes with? For instance say I have 10 subnets 10.0.1.0/24 10.0.10.0/24 would I be able to scan all those networks at once off of our 6509 core. Any recommendation on how to deploy would be appreciated.
This is not really a function of the IDS, but more of the switch that it's connected to. you basically plug the monitoring/sniffing port of the 4250 into a switch port, then use either the "span" command or VACL's to send traffic from the switch to that sniffing port.
In short though, with a 6509 you can defintely span multiple VLANs/subnets, no problem there.
You might want to look at the IDSM-2, which is an IDS on a blade that slots right into the 6509, everything is internal to the switch then.