Advanced Configuration and Management Guide
Layer 3 Filters
Layer 3 filters control a device’s transmission and receipt of packets based on routing protocol information in the
packets. The routing switches and switch provide the following types of Layer 3 filters:
• IP forwarding filters (same as IP access policies, see “IP Access Policies” on page C-7)
• IP/RIP route filters
• IP/RIP neighbor filters
• IPX forwarding filters
• IPX RIP route and neighbor filters
• IPX SAP service filters
• AppleTalk zone filters
• AppleTalk network filters
• BGP route address filters
• BGP route AS-path filters
• BGP route community filters
• IP/RIP redistribution filters
• OSPF redistribution filters
• BGP redistribution filters
IP Filters
IP filters control the IP packets that the device sends and receives and the routes that the device learns or
advertises. IP forwarding filters (IP Access policies) control transmission and receipt of IP packets, while
IP/RIP route and neighbor filters control the routes that the device leans or advertises. Route filters filter on
specific network addresses while neighbor filters filter on the IP addresses of the IP/RIP neighbors.
IP Forwarding Filters
IP forwarding filters determine whether to forward or drop an IP packet. IP forwarding filters on a switch or routing
switch are called “IP access policies”. See “IP Access Policies” on page C-7.
IP/RIP Route Filters
IP/RIP route filters control the routes that a device learns and advertises. Figure D.4 shows an example of a port
with IP/RIP route filters. The port has filters for the inbound direction and the outbound direction. Notice that the
same filter can be used for both directions. The inbound filters control the routes that the device learns; denied
routes are not learned by the device. Outbound filters control the routes that the device advertises; denied routes
are not advertised to RIP neighbors.
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