I have a customer with 9 locations connected together via T1 circuts. The routers at the sites are Cisco 1721's with T1 WICs. There are 60 Win2K servers with an Active Directory DC at each site. Cisco's recommendation only addresses the router at the edge and will not work for the other routers in this scenerio. Is there any way to block Blaster at the router level, using the 1721's that are currently in place, without stopping valid communications between sites and servers?