Prefix List

Configure IPv4 and IPv6 prefix lists for route filtering and access control. Prefix lists provide a powerful mechanism to filter routes based on network prefixes and prefix lengths, commonly used in routing policies, route maps, and access control.

Diagram

Classes

iosxr

Name	Type	Constraint	Mandatory	Default Value
devices	List	devices	No
device_groups	List	device_groups	No
global	Class	global	No

devices (iosxr)

Name	Type	Constraint	Mandatory	Default Value
configuration	Class	configuration	No

device_groups (iosxr)

Name	Type	Constraint	Mandatory	Default Value
configuration	Class	configuration	No

global (iosxr)

Name	Type	Constraint	Mandatory	Default Value
configuration	Class	configuration	No

configuration (iosxr.devices)

Name	Type	Constraint	Mandatory	Default Value
prefix_lists	Class	prefix_lists	No

prefix_lists (iosxr.devices.configuration)

Name	Type	Constraint	Mandatory	Default Value
ipv4	List	ipv4	No
ipv6	List	ipv6	No

ipv4 (iosxr.devices.configuration.prefix_lists)

Name	Type	Constraint	Mandatory	Default Value
name	String	max: 32	Yes
entries	List	entries	No

ipv6 (iosxr.devices.configuration.prefix_lists)

Name	Type	Constraint	Mandatory	Default Value
name	String	max: 32	Yes
entries	List	entries	No

entries (iosxr.devices.configuration.prefix_lists.ipv4)

Name	Type	Constraint	Mandatory	Default Value
sequence	Integer	min: 1, max: 2147483646	Yes
action	Choice	deny, permit	No
exact_length	Integer	min: 0, max: 32	No
length	Integer	min: 0, max: 32	No
max_length	Integer	min: 0, max: 32	No
min_length	Integer	min: 0, max: 32	No
prefix	IP		No
remark	String		No

entries (iosxr.devices.configuration.prefix_lists.ipv6)

Name	Type	Constraint	Mandatory	Default Value
sequence	Integer	min: 1, max: 2147483646	Yes
action	Choice	deny, permit	No
exact_length	Integer	min: 0, max: 128	No
length	Integer	min: 0, max: 128	No
max_length	Integer	min: 0, max: 128	No
min_length	Integer	min: 0, max: 128	No
prefix	IP		No
remark	String		No
zone	Integer	min: 0, max: 4294967295	No

Guidelines and Limitations

• IPv6 prefix list remarks (remark) are not supported via gNMI. Use remarks only in IPv4 prefix lists.

Example YAML Code:

Example-1: IPv4 prefix list with permit and deny entries.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        prefix_lists:
          ipv4:
            - name: MGMT_NETWORKS
              entries:
                - sequence: 10
                  action: permit
                  prefix: 192.168.1.0
                  length: 24
                  exact_length: 24
                - sequence: 20
                  action: deny
                  prefix: 0.0.0.0
                  length: 0

Example-2: IPv4 prefix list with remarks and range matching.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        prefix_lists:
          ipv4:
            - name: MGMT_NETWORKS
              entries:
                - sequence: 5
                  remark: "Allow management subnet"
                - sequence: 10
                  action: permit
                  prefix: 192.168.1.0
                  length: 24
                  exact_length: 24
                - sequence: 20
                  action: permit
                  prefix: 10.0.0.0
                  length: 8
                  min_length: 8
                  max_length: 24
                - sequence: 25
                  remark: "Deny all others"
                - sequence: 30
                  action: deny
                  prefix: 0.0.0.0
                  length: 0

Example-3: IPv6 prefix list with permit/deny entries and zone.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        prefix_lists:
          ipv6:
            - name: IPV6_MGMT
              entries:
                - sequence: 10
                  action: permit
                  prefix: "2001:db8:1::"
                  length: 48
                  min_length: 64
                  max_length: 128
                - sequence: 20
                  action: deny
                  prefix: "::"
                  length: 0

Example-4: IPv4 and IPv6 prefix lists on one device.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        prefix_lists:
          ipv4:
            - name: MGMT_NETWORKS
              entries:
                - sequence: 10
                  action: permit
                  prefix: 192.168.1.0
                  length: 24
                  exact_length: 24
            - name: LOOPBACK_NETWORKS
              entries:
                - sequence: 10
                  action: permit
                  prefix: 172.16.0.0
                  length: 12
                  exact_length: 32
          ipv6:
            - name: IPV6_MGMT
              entries:
                - sequence: 10
                  action: permit
                  prefix: "2001:db8:1::"
                  length: 48
                  min_length: 64
                  max_length: 128
            - name: IPV6_LOOPBACKS
              entries:
                - sequence: 10
                  action: permit
                  prefix: "2001:db8:ffff::"
                  length: 48
                  exact_length: 128