This document demonstrators how to deploy WFilter with a cisco 2950 switch. The network topology diagram:
You need to setup a mirroring port in the cisco 2950 switch.
In this example, internet router is connected to "Port 23", WFilter computer is connected to "Port 22". To monitor all internet traffic, we need to mirror "port 23" to "port 22".
monitor session 1 source interface Fa0/23
monitor session 1 destination interface Fa0/22 ingress vlan 1
Please notice, the mirroring port of cisco 2950 is recv-only by default. However WFilter shall be able to send packages for blocking purpose. So in this example, we add "ingress vlan 1" parameter to enable outgoing traffic on port 22. If your switch does not support "ingress" parameter, you need to add another NIC as the blocking adapter.