# BGP AS-Path Access List Configuration

A BGP AS-path access list serves as a packet filtering mechanism. The NetScreen device can consult a list and permit or deny BGP packets based on the regular expressions contained in the list. Regular expressions allow you to specify a string to search for routes that you want to filter, either accepting or denying them.

### To Configure an AS-Path Access List

1. AS Path Access List ID: Enter a number to identify the AS path access list.

2. Select Permit to accept routes that match the As Path String, or Deny to deny routes that match the As Path String.

3. As Path String: Enter a regular expression. For more information, see Regular Expression.

4. Action: Select Add to add the AS-path access list. The AS path access list entry you configured appears on the page. Click Remove to remove the entry.