FTOS Configuration Guide for the C-Series - Force10 Networks

Use these commands in the following sequence, starting in the CONFIGURATION mode to configure an
AS-PATH ACL to filter a specific AS_PATH value.
Step Command Syntax Command Mode Purpose
1 ip as-path access-list
as-path-name
2
3
4
5
{deny | permit} filter
parameter
Regular Expressions as filters
CONFIGURATION Assign a name to a AS-PATH ACL and enter
AS-PATH ACL mode.
CONFIG-AS-PATH Enter the parameter to match BGP AS-PATH for
filtering. This is the filter that will be used to match
the AS-path. The entries can be any format,
letters, numbers, or regular expressions.
This command can be entered multiple times if
multiple filters are desired.
See Table 50 for accepted expressions.
exit AS-PATH ACL Return to CONFIGURATION mode
router bgp as-number CONFIGURATION Enter ROUTER BGP mode.
neighbor {ip-address |
peer-group-name}
filter-list as-path-name
{in | out}
CONFIG-ROUTER-
BGP
Use a configured AS-PATH ACL for route filtering
and manipulation.
If you assign an non-existent or empty AS-PATH
ACL, the software allows all routes.
Regular expressions are used to filter AS paths or community lists. A regular expression is a special
character used to define a pattern that is then compared with an input string.
For an AS-path access list as shown in the commands above, if the AS path matches the regular expression
in the access list, then the route matches the access list.
FTOS Configuration Guide, version 7.7.1.0 493