IP Access List

Access lists provide packet filtering and traffic classification on NX-OS through ordered sequences of permit/deny rules that match on Layer 3 and Layer 4 header fields including protocol, source/destination prefixes, ports, DSCP, and TCP flags. Each ACL supports per-ACE statistics, fragment handling policies, address and port groups for object-based matching, ICMP type/code filtering, HTTP method matching, packet length operators, time-range restrictions, VLAN/VNI-based filtering, TTL matching, capture sessions, IGMP type filtering, telemetry actions, and redirect options. Access lists are applied to interfaces for ingress/egress traffic filtering and referenced by other features such as route maps, QoS policies, and DHCP snooping for comprehensive traffic control and security enforcement.

Diagram

Classes

configuration (nxos.devices)

Name	Type	Constraint	Mandatory	Default Value
ip_access_lists	List	`[ip_access_lists]`	No

ip_access_lists (nxos.devices.configuration)

Name	Type	Constraint	Mandatory
name	String		Yes
fragments	Choice	`permit-all`, `deny-all`	No
ignore_routable	Boolean	`true`, `false`	No
statistics_per_entry	Boolean	`true`, `false`	No
entries	List	`[entries]`	No

entries (nxos.devices.configuration.ip_access_lists)

Name	Type	Constraint	Mandatory
sequence_number	Integer	min: `1`, max: `4294967295`	Yes
remark	String		No
action	Choice	`permit`, `deny`	No
protocol	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
source	Class	`[source]`	No
destination	Class	`[destination]`	No
dscp	Integer	min: `0`, max: `63`	No
fragment	Boolean	`true`, `false`	No
log	Boolean	`true`, `false`	No
established	Boolean	`true`, `false`	No
ack	Boolean	`true`, `false`	No
fin	Boolean	`true`, `false`	No
psh	Boolean	`true`, `false`	No
rst	Boolean	`true`, `false`	No
syn	Boolean	`true`, `false`	No
urg	Boolean	`true`, `false`	No
icmp_type	Integer	min: `0`, max: `256`	No
icmp_code	Integer	min: `0`, max: `256`	No
icmp_message	String		No
http_method	Choice	`get`, `put`, `head`, `post`, `delete`, `trace`, `connect`	No
time_range	String		No
redirect	String		No
packet_length_operator	Choice	`none`, `eq`, `neq`, `lt`, `gt`, `range`	No
packet_length_1	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
packet_length_2	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
precedence	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
vlan	Integer	min: `0`, max: `4095`	No
vni	String		No
rev	Boolean	`true`, `false`	No
tcp_flags_mask	Integer	min: `0`, max: `64`	No
tcp_option_length	Integer	min: `0`, max: `41`	No
igmp_type	Integer	min: `0`, max: `16`	No
capture_session	Integer	min: `0`, max: `48`	No
dscp_mask	Integer	min: `0`, max: `63`	No
load_share	Boolean	`true`, `false`	No
priority_all	Boolean	`true`, `false`	No
protocol_mask	String		No
redirect_all	String		No
telemetry_path	Boolean	`true`, `false`	No
telemetry_queue	Boolean	`true`, `false`	No
tos	Integer	min: `0`, max: `15`	No
ttl	Integer	min: `0`, max: `255`	No

source (nxos.devices.configuration.ip_access_lists.entries)

Name	Type	Constraint	Mandatory
prefix	String		No
prefix_length	Integer	min: `0`, max: `32`	No
prefix_mask	String		No
address_group	String		No
port_operator	Choice	`none`, `eq`, `neq`, `lt`, `gt`, `range`	No
port_1	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
port_2	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
port_group	String		No

destination (nxos.devices.configuration.ip_access_lists.entries)

Name	Type	Constraint	Mandatory
prefix	String		No
prefix_length	Integer	min: `0`, max: `32`	No
prefix_mask	String		No
address_group	String		No
port_operator	Choice	`none`, `eq`, `neq`, `lt`, `gt`, `range`	No
port_1	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
port_2	Any	String or Integer or String[Regex: `^.[\$\%]\{.$`]	No
port_group	String		No

Examples

Example 1: Management plane protection ACL — restrict SSH and SNMP access to trusted subnets

nxos:
  devices:
    - name: SPINE1
      configuration:
        ip_access_lists:
          - name: ACL-MGMT-ACCESS
            statistics_per_entry: true
            entries:
              - sequence_number: 10
                remark: "Allow SSH from management subnet"
              - sequence_number: 20
                action: permit
                protocol: tcp
                source:
                  prefix: 10.50.202.0
                  prefix_length: 24
                destination:
                  prefix: any
                  port_operator: eq
                  port_1: 22
              - sequence_number: 30
                remark: "Allow SNMP from monitoring servers"
              - sequence_number: 40
                action: permit
                protocol: udp
                source:
                  prefix: 10.50.100.0
                  prefix_length: 24
                destination:
                  prefix: any
                  port_operator: eq
                  port_1: 161
              - sequence_number: 50
                remark: "Allow TACACS from AAA servers"
              - sequence_number: 60
                action: permit
                protocol: tcp
                source:
                  prefix: 10.50.100.10
                  prefix_length: 32
                destination:
                  prefix: any
                  port_operator: eq
                  port_1: 49
              - sequence_number: 1000
                action: deny
                protocol: ip
                source:
                  prefix: any
                destination:
                  prefix: any
                log: true

Example 2: VXLAN fabric infrastructure ACL — permit BFD, BGP, and VXLAN UDP traffic between spine and leaf

nxos:
  devices:
    - name: LEAF1
      configuration:
        ip_access_lists:
          - name: ACL-FABRIC-INFRA
            statistics_per_entry: true
            entries:
              - sequence_number: 10
                remark: "Allow BGP between fabric peers"
              - sequence_number: 20
                action: permit
                protocol: tcp
                source:
                  prefix: 10.1.10.0
                  prefix_length: 24
                destination:
                  prefix: 10.1.10.0
                  prefix_length: 24
                  port_operator: eq
                  port_1: 179
              - sequence_number: 30
                remark: "Allow VXLAN encapsulated traffic"
              - sequence_number: 40
                action: permit
                protocol: udp
                source:
                  prefix: 10.1.200.0
                  prefix_length: 24
                destination:
                  prefix: 10.1.200.0
                  prefix_length: 24
                  port_operator: eq
                  port_1: 4789
              - sequence_number: 50
                remark: "Allow ICMP for troubleshooting"
              - sequence_number: 60
                action: permit
                protocol: icmp
                source:
                  prefix: 10.1.0.0
                  prefix_length: 16
                destination:
                  prefix: 10.1.0.0
                  prefix_length: 16

Example 3: Tenant traffic filtering ACL with TCP flags, DSCP marking, and logging on a border leaf

nxos:
  devices:
    - name: BORDER-LEAF1
      configuration:
        ip_access_lists:
          - name: ACL-TENANT-BLUE-IN
            statistics_per_entry: true
            fragments: deny-all
            entries:
              - sequence_number: 10
                remark: "Allow established TCP sessions"
              - sequence_number: 20
                action: permit
                protocol: tcp
                source:
                  prefix: any
                destination:
                  prefix: 192.168.1.0
                  prefix_length: 24
                established: true
              - sequence_number: 30
                remark: "Allow HTTPS inbound to web tier"
              - sequence_number: 40
                action: permit
                protocol: tcp
                source:
                  prefix: any
                destination:
                  prefix: 192.168.1.0
                  prefix_length: 24
                  port_operator: eq
                  port_1: 443
                dscp: 46
              - sequence_number: 50
                remark: "Allow DNS queries to tenant DNS"
              - sequence_number: 60
                action: permit
                protocol: udp
                source:
                  prefix: any
                destination:
                  prefix: 192.168.1.0
                  prefix_length: 24
                  port_operator: eq
                  port_1: 53
              - sequence_number: 70
                remark: "Deny and log all other traffic"
              - sequence_number: 80
                action: deny
                protocol: ip
                source:
                  prefix: any
                destination:
                  prefix: any
                log: true

Example 4: Advanced ACL with TTL matching, IGMP filtering, capture session, time-range, and telemetry

nxos:
  devices:
    - name: LEAF2
      configuration:
        ip_access_lists:
          - name: ACL-ADVANCED-SECURITY
            statistics_per_entry: true
            ignore_routable: true
            entries:
              - sequence_number: 10
                remark: "Capture suspicious traffic for analysis"
              - sequence_number: 20
                action: permit
                protocol: tcp
                source:
                  prefix: 10.99.0.0
                  prefix_length: 16
                destination:
                  prefix: any
                  port_operator: eq
                  port_1: 443
                capture_session: 1
                telemetry_queue: true
              - sequence_number: 30
                remark: "Allow IGMP queries from routers"
              - sequence_number: 40
                action: permit
                protocol: igmp
                source:
                  prefix: 10.1.0.0
                  prefix_length: 16
                destination:
                  prefix: any
                igmp_type: 1
              - sequence_number: 50
                remark: "Permit ICMP echo with TTL check"
              - sequence_number: 60
                action: permit
                protocol: icmp
                source:
                  prefix: any
                destination:
                  prefix: 172.16.0.0
                  prefix_length: 12
                icmp_message: echo
                ttl: 64
              - sequence_number: 70
                remark: "Allow HTTP during business hours"
              - sequence_number: 80
                action: permit
                protocol: tcp
                source:
                  prefix: 10.20.0.0
                  prefix_length: 16
                destination:
                  prefix: any
                  port_operator: eq
                  port_1: 80
                http_method: get
                time_range: BUSINESS-HOURS
              - sequence_number: 90
                remark: "Redirect traffic to inspection appliance"
              - sequence_number: 100
                action: permit
                protocol: ip
                source:
                  prefix: 10.30.0.0
                  prefix_length: 24
                destination:
                  prefix: any
                redirect: eth1/48
                load_share: true
              - sequence_number: 1000
                action: deny
                protocol: ip
                source:
                  prefix: any
                destination:
                  prefix: any
                log: true

Access lists provide packet filtering and traffic classification on NX-OS through ordered sequences of permit/deny rules that match on Layer 3 and Layer 4 header fields including protocol, source/destination prefixes, ports, DSCP, and TCP flags. Each ACL supports per-ACE statistics, fragment handling policies, address and port groups for object-based matching, ICMP type/code filtering, HTTP method matching, packet length operators, time-range restrictions, and VLAN/VNI-based filtering. Access lists are applied to interfaces for ingress/egress traffic filtering and referenced by other features such as route maps, QoS policies, and DHCP snooping for comprehensive traffic control and security enforcement.