An IP prefix list contains single or multiple IP addresses that are assigned access permissions for route advertisement. The IP addresses in this list are processed sequentially. IP prefix lists are referenced through BGP neighbor filters or route maps with in or out direction.

For example, you can add the IP address 192.168.100.3/27 to the IP prefix list and deny the route from being redistributed to the northbound router. You can also append an IP address with less-than-or-equal-to (le) and greater-than-or-equal-to (ge) modifiers to grant or limit route redistribution. For example, 192.168.100.3/27 ge 24 le 30 modifiers match subnet masks greater than or equal to 24-bits and less than or equal to 30-bits in length.

Note:

The default action for a route is Deny. When you create a prefix list to deny or permit specific routes, be sure to create an IP prefix with no specific network address (select Any from the dropdown list) and the Permit action if you want to permit all other routes.

Prerequisites

Verify that you have a tier-0 logical router configured. See Create a Tier-0 Logical Router.

Procedure

  1. From your browser, log in with admin privileges to an NSX Manager at https://nsx-manager-ip-address.
  2. Select Networking > Routing from the navigation panel.
  3. Select the tier-0 logical router.
  4. Click the Routing tab and select IP Prefix Lists from the drop-down menu.
  5. Click Add.
  6. Enter a name for the IP prefix list.
  7. Click Add to specify a prefix.
    1. Enter an IP address in CIDR format.

      For example, 192.168.100.3/27.

    2. Select Deny or Permit from the drop-down menu.
    3. (Optional) Set a range of IP address numbers in the le or ge modifiers.

      For example, set le to 30 and ge to 24.

  8. Repeat the previous step to specify additional prefixes.
  9. Click Add at the bottom of the window.