With IPX RIP policies, you can configure route filters to give you greater control over the routing of IPX packets from one area of an IPX internetwork to another. Using route filters helps maximize the use of the available bandwidth throughout the IPX internetwork, and helps improve network security by restricting a user's view of other networks.
You can configure inbound and outbound route filters on a per-interface basis, instructing the interface to advertise, accept, or drop filtered RIP packets. The action parameter that you define for the filter determines whether the router advertises, accepts, or drops RIP packets from routers that match the filter criteria.
A Service Advertisement Protocol (SAP) filter is a pattern for matching a service name or service network. Passport scans incoming and outgoing SAP packets to see whether certain fields in the packet match the filter. When you configure the filter, you can specify what Passport does with the services in the packet when it finds a match. You can create SAP filters on Passport in your network to regulate both incoming and outgoing SAP advertisements. You can use SAP filters to control the size of resident SAP service tables and reduce bandwidth usage on your network due to SAP broadcast overhead.
You can also create SAP filters as a security mechanism to restrict a user's view of services located elsewhere on the network. As a result, you can tailor SAP filters to your site requirements, improving network security by controlling access and preserving bandwidth by limiting the SAP packet traffic.