Configuring An As Path Access List - Motorola BSR 2000 Configuration And Management Manual

Release 1.0
Note: Any type of list always has an assumed deny all entry as the last
statement. If there are no matches at the end, the route or match (depending
on the type of list and/or how it is used) is denied.
The following commands, also executed in Global Configuration mode, enable BGP,
specify an AS, and apply Access List 4 to a neighbor. The example instructs the router
to pass all network information received from the BGP neighbor 156.30.10.22
through access list 4.

Configuring an AS Path Access List

Autonomous System (AS) paths can be applied to an AS path access list by using
permit and deny arguments. The neighbor filter-list command applies an AS path
access list for inbound and outbound updates to a BGP neighbor. The match as_path
command adds a match clause to a route map.
Use the ip as-path access-list command in Global Configuration mode to define an
AS path access list:
MOT(config)#ip as-path access-list <1-199> {permit | deny} <LINE>
where:
Example
The commands in the example below configure a router with two AS path access lists.
Routes that pass AS path access list 1 are sent to one destination. Routes that pass AS
path access list 2 are accepted from another destination. The commands, executed in
Global Configuration mode, specify permit and deny conditions for AS path access
lists 1 and 2.
526360-001-00 Rev. B
MOT(config)#access-list 4 permit any
MOT(config)#router bgp 100
MOT(config-bgp)#neighbor 156.30.10.22 distribute-list 4 in
1-199 is the access list number.
permit specifies the packets to forward from the specified access list.
deny specifies the packets to reject from the specified access list.
LINE is a valid path regular expression.
MOT(config)#ip as-path access-list 1 permit _200
MOT(config)#ip as-path access-list 1 permit ^100
MGBI
Configuring BGP
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