August 2005
Intermediate to advanced
798 pages
31h 12m
English
ip as-path access-list — global
ip as-path access-listaccess-list{permit | deny}as-regexno ip as-path access-listaccess-list{permit | deny}as-regex
A BGP access list
None
This command allows you to build an access list for BGP autonomous system (AS) paths. These lists can be applied to a neighbor with the filter-list option to the neighbor command. access-list is a number that identifies the list; as-regex is a regular expression that matches AS paths. For more information on valid regular expressions for BGP, see Chapter 10.
The following commands create an AS-path access list that denies (blocks) routes that include AS 111. This access list is then applied to routes that are sent to the BGP neighbor 11.1.1.1.
ip as-path access-list 1 deny _111_ router bgp 120 network 10.1.0.0 neighbor 11.1.1.1 remote-as 200 neighbor 11.1.1.1 filter-list 1 out