IPX SAP Filters

Servers and routers on an IPX network exchange information about the name, type, and location of the various service providers on the internetwork by way of SAP packets. This information is distributed to users through SAP packets. By limiting the propagation of this information, SAP filters provide limited security at the servers and reduce the bandwidth required by the SAP exchanges.

There are two types of service information filters:

• Outgoing SAP filters (service advertisement filters)

  Outgoing SAP filters restrict the propagation of the SAP information that is known to the router. An outgoing SAP filter specifies the service provider and the potential recipient of the information. The service provider is defined by a service name and service type. The recipient is defined as an outbound interface or interface group. The filter is applied to all servers, users, and routers that would receive the SAP information through the interface. In large NetWare^® internetworks, outbound SAP filtering can save valuable WAN bandwidth, although the NetWare Link Services Protocol^TM (NLSP^TM) protocol might offer greater bandwidth savings.

• Incoming SAP filters (service acceptance filters)

  Incoming SAP filters let the router discard information about a particular service provider. The filtered SAP information is not recorded in the local SAP information table or propagated to other routers or servers. The SAP filter includes the service name and service type. An incoming SAP filter can also specify the source of the SAP information to be filtered. The source identifies the interface from which the SAP information was received.

  NOTE:  SAP filters work only on routers running the RIP and SAP protocols. They do not work on routers running the NLSP protocol. For filtering to work, either IPXRTR must be configured for RIP/SAP only, or the bind options on selected interfaces must be set up to read RIP=Yes , SAP=Yes , and NLSP=No .