Routing based on source address is called "Policy Routing". IF you are on a cisco box, create an extended access-list specifying the source Ip's, and then match that access list in a route map to set the next hop. Apply the route map on ports facing that customer, building a chain from edge (facing the customer) to border (facing the internet. Good Luck, Ejay -----Original Message----- From: Daniel Abbey [mailto:dabbey@edeltacom.net] Sent: Monday, March 17, 2003 10:20 AM To: nanog@merit.edu Cc: cisco-digest@groupstudy.com; isp-outsourcing@isp-outsourcing.com Subject: FW: Controlling outbound traffic in a multihomed BGP environment How can you control outbound traffic from a single subnet - meaning forcing all its outbound traffic out a single bgp edge router in a multihomed environment. Here is the scenario: 1. Inbound traffic is engineered using prepends - meaning to force inbound traffic through a particular router, we are using prepends to make one path seem better than the other on the outside. 2. Local preferences are set to control general outbound traffic to specific ISPs - those that are one or two hops away. 3. Now, I have a customer whose traffic I'll prefer to force out a single bgp edge router - all his traffic, no specific ones. The IGP is OSPF, and there are several different distribution routers between the access IGP router and the core/edge bgp routers.