Dell SmartFabric OS10 User Guide Release 10.5.3

PDF

ip as-path access-list

Create an AS-path ACL filter for BGP routes using a regular expression. The AS values should be configured only in the plain format (regular expressions) and not in the dotted format. This works similar to the AS values received in the BGP update messages.

Syntax

ip as-path access-list name {deny | permit} regexp-string

Parameters

name — Enter an access list name.
deny | permit — Reject or accept a matching route.
regexp-string — Enter a regular expression string to match an AS-path route attribute.

Defaults

Not configured

Command Mode

CONFIGURATION

Usage Information

You can specify an access-list filter on inbound and outbound BGP routes. The ACL filter consists of regular expressions. If a regular expression matches an AS path attribute in a BGP route, the route is rejected or accepted. The AS path does not contain the local AS number. The no version of this command removes a single access list entry if you specify deny and a regexp. Otherwise, the entire access list is removed.

The following table provides a list of characters that you can use in the regular expression string and indicates whether the character is supported or not:

Table 1. Special characters supported in regular expressionSpecial characters supported in regular expression
Character	Supported/Not supported
Question mark (?)	Not supported
Pipe (\|)	Supported
Plus (+)	Supported
Caret (^)	Supported; use the caret (^) character to represent the beginning of a new line.
Dollar ($)	Supported
Square brackets ([ ])	Supported
Asterisk (*)	Supported
Dot (.)	Supported
Backslash (\)	Supported; precede the character with a backslash(\). For example, enter \\.
Double quotes (")	Supported; precede the character with a backslash(\). For example, enter \".
Curly brackets ({ })	Not supported; as a workaround, precede the open and close parentheses with a backslash, for example, "\(" and "\)".
Parentheses (())	Supported
Comma (,)	Supported; comma(,) can be used to match space in AS-PATH
Space	Not supported; as a workaround, use comma(,) or [[:punct:]].
Underscore ( _ )	Not supported

Example

OS10(config)# ip as-path access-list abc deny 123

Supported Release

10.3.0E or later