SAP Filters

The Cisco IOS permits a network administrator to filter on the basis of which SAP services a device sends from and receives into its SAP table. SAP filters are commonly used on an internetwork to limit the amount of SAP traffic sent and received by a router.

Many IPX networks use SAP filters to reduce the number of SAP messages sent over WAN interfaces, thereby reducing traffic load. Filtering received SAP advertisements can reduce the number of IPX services a router has in RAM and can provide limited network security. The limited network security is accomplished by not allowing the IOS device to provide SAP table entries for services that want to remain somewhat hidden on an IPX network. For more information on filtering IPX packets, ...

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