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Use Route Maps and Other Filters to Filter and Alter BGP and OSPF Routes | Page 15
BGP: Configuring Distribute Filters
Use a numbered ACL instead of a named ACL
This example demonstrates a numbered ACL by discarding all routes to 52.0.0.0.
In line with industry standards, the wildcard mask is required but its value has no effect. The
ACL always applies to all prefix lengths.
7. Check that the IP route table no longer includes 52.0.0.0/8.
awplus(config-router)#
do show ip route
Codes: C - connected, S - static, R - RIP, B - BGP
O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
* - candidate default
B 45.0.0.0/8 [20/0] via 45.45.45.46, vlan1, 00:00:08
C 45.45.45.0/24 is directly connected, vlan1
C 64.0.0.0/4 is directly connected, vlan64
1. Create a numbered ACL.
awplus(config)#
access-list 1301 deny 52.0.0.0 0.0.0.255
awplus(config)#
access-list 1301 permit any
2. Set that ACL as the filter for the BGP neighbor 45.45.45.46.
awplus(config)#
router bgp 34567
awplus(config-router)#
neighbor 45.45.45.46 distribute-list 1301 in
3. Shut down the neighbor, and then bring it up again.
awplus(config-router)#
neighbor 45.45.45.46 shutdown
awplus(config-router)#
neighbor 45.45.45.46 no shutdown