Please excuse me if this is a dumb question, but I am going to ask anyhow (I am a novice). If I have multiple switches plugged into the switch ports on the back of a Cisco 871 router, is it possible to filter the traffic that travels between these two ports? So, all of the computers on this hypothetical network would be on the same subnet, but hosts with IP addresses from 192.168.0.50-192.168.0.100 would be accessible from the switch attached to one of the Cisco switch ports and hosts with IP addresses from192.168.0.101-192.168.0.150 would be accessible from another switch attached to a different switch port on the Cisco router. Can the traffic between these two address ranges be filtered by the Cisco router? I do understand the typical way of doing this would be to utilize VLANs, but this requires the rather expensive "Advanced IP Services" IOS. Thanks.