Validate Security ACLs on Catalyst 9000 Switches

Introduction

This document describes how to verify and troubleshoot ACLs (access control lists) on Catalyst 9000 series switches.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these hardware versions:

• C9200
• C9300
• C9400
• C9500
• C9600

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Note: Consult the appropriate configuration guide for the commands used to enable these features on other Cisco platforms.

Background Information

ACLs filter traffic as it passes through a router or switch and permit or deny packets that cross specified interfaces. An ACL is a sequential collection of permit and deny conditions that apply to packets. When a packet is received on an interface, the switch compares the fields in the packet against any applied ACLs in order to verify that the packet has the required permissions to be forwarded, based on the criteria specified in the access lists. One by one, it tests packets against the conditions in an access list. The first match decides whether the switch accepts or rejects the packets. Because the switch stops testing after the first match, the order of conditions in the list is critical. If no conditions match, the switch rejects the packet. If there are no restrictions, the switch forwards the packet; otherwise, the switch drops the packet. The switch can use ACLs on all packets it forwards.

You can configure access lists in order to provide basic security for your network. If you do not configure ACLs, all packets that pass through the switch can be allowed onto all network parts. You can use ACLs in order to control which hosts can access different parts of a network or to decide which types of traffic are forwarded or blocked at router interfaces. For example, you can forward e-mail traffic but not Telnet traffic.

Terminology

ACL Resource Utilization Examples

Three examples are given here in order to demonstrate how ACLs consume TCAM, L4OPs, and VCUs.

Example 1. IPv4 TCAM

access-list 101 permit ip any 10.1.1.0 0.0.0.255
access-list 101 permit ip any 10.1.2.0 0.0.0.255
access-list 101 permit ip any 10.1.3.0 0.0.0.255
access-list 101 permit ip any 10.1.4.0 0.0.0.255
access-list 101 permit ip any 10.1.5.0 0.0.0.255

Example 2. IPv4 TCAM/L4OP/VCU

ip access-list extended TEST
10 permit tcp 192.168.1.0 0.0.0.255 any neq 3456          <-- 1 L4OP, 1 VCU
20 permit tcp 10.0.0.0 0.255.255.255 any range 3000 3100  <-- 1 L4OP, 2 VCU
30 permit tcp 172.16.0.0 0.0.255.255 any range 4000 8000  <-- 1 L4OP, 2 VCU
40 permit tcp 192.168.2.0 0.0.0.255 gt 10000 any eq 20000 <-- 2 L4OP, 2 VCU

Example 3. IPv6 TCAM/L4OP/VCU

IPv6 ACEs use two TCAM entries versus one for IPv4. In this example, four ACEs consume eight TCAM instead of four.

ipv6 access-list v6TEST
sequence 10 deny ipv6 any 2001:DB8:C18::/48 fragments
sequence 20 deny ipv6 2001:DB8::/32 any
sequence 30 permit tcp host 2001:DB8:C19:2:1::F host 2001:DB8:C18:2:1::1 eq bgp  <-- One L4OP & VCU
sequence 40 permit tcp host 2001:DB8:C19:2:1::F eq bgp host 2001:DB8:C18:2:1::1  <-- One L4OP & VCU

Topology

The 9300 VLAN 10 SVI uses one of the two IP addresses shown in this image, based on whether a forward or drop result is shown in the examples.

Configure and Verify

This section covers how to verify and troubleshoot ACL programming in software and hardware.

Scenario 1. PACL (IP ACL)

PACLs are assigned to a Layer 2 interface.

• Security Boundary: Ports or VLANs
• Attachment: Layer 2 Interface
• Direction: Ingress or Egress (one at a time)
• Supported ACL Types: MAC ACL & IP ACLs (standard or extended)

Configure PACL with IP ACL

9500H(config)#ip access-list extended TEST          <-- Create a named extended ACL
9500H(config-ext-nacl)#permit ip host 10.1.1.1 any
9500H(config-ext-nacl)#permit udp host 10.1.1.1 eq 1000 host 10.1.1.2

9500H#show access-lists TEST                        <-- Display the ACL configured 
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any
    20 permit udp host 10.1.1.1 eq 1000 host 10.1.1.2

9500H(config)#interface twentyFiveGigE 1/0/1        <-- Apply ACL to Layer 2 interface  
9500H(config-if)#ip access-group TEST in

9500H#show running-config interface twentyFiveGigE 1/0/1
Building configuration...

Current configuration : 63 bytes
!
interface TwentyFiveGigE1/0/1
 ip access-group TEST in                             <-- Display the ACL applied to the interface 
end

Verify PACL

Retrieve the IF_ID associated with the interface.

9500H#show platform software fed active ifm interfaces ethernet
Interface                         IF_ID               State 
----------------------------------------------------------------
TwentyFiveGigE1/0/1               0x00000008          READY     <-- IF_ID value for Tw1/0/1

Verify the Class group ID (CG ID) bound to the IF_ID.

9500H#show platform software fed active acl interface 0x8       <-- IF_ID with leading zeros omitted 
########################################################
########                              ##################
#######   Printing Interface Infos     #################
########                              ##################
########################################################

INTERFACE: TwentyFiveGigE1/0/1                                  <-- Confirms the interface matches the IF_ID
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7f8cfc02de98
    Interface handle: 0x7e000028
    Interface Type: Port                                        <-- Type: Port indicates Layer 2 interface 
    if-id: 0x0000000000000008                                   <-- IF_ID 0x8 is correct
    Input IPv4: Policy Handle: 0x5b000093
        Policy Name: TEST                                       <-- The named ACL bound to this interface 
             CG ID: 9                                           <-- Class Group ID for this entry 
       CGM Feature: [0] acl                                     <-- Feature is ACL
        Bind Order: 0

ACL information associated with the CG ID.

9500H#show platform software fed active acl info acl-cgid 9  <-- The CG ID associated to the ACL TEST
########################################################
#########                             ##################
########      Printing CG Entries      #################
#########                             ##################
########################################################
===================================
ACL CG (acl/9): TEST type: IPv4     <-- feature ACL/CG ID 9: ACl name TEST : ACL type IPv4 
Total Ref count 1
---------------------------------
1 Interface                         <-- ACL is applied to one interface 
---------------------------------
  region reg_id: 10
    subregion subr_id: 0
      GCE#:1 #flds: 2 l4:N matchall:N deny:N             <-- #flds: 2 = two fields in entry | l4:N (no Layer 4 port match) 
        Result: 0x01010000
        ipv4_src: value = 0x0a010101, mask = 0xffffffff  <-- src 0x0a010101 hex = 10.1.1.1 | mask 0xffffffff = exact host match
        ipv4_dst: value = 0x00000000, mask = 0x00000000  <-- dst & mask = 0x00000000 = match any
       GCE#:1 #flds: 4 l4:Y matchall:N deny:N            <-- #flds: 4 = four fields in entry | l4:Y (ACE uses UDP port L4 match)
        Result: 0x01010000
        ipv4_src: value = 0x0a010101, mask = 0xffffffff  <-- Exact match (host) 10.1.1.1 
        ipv4_dst: value = 0x0a010102, mask = 0xffffffff  <-- Exact match (host) 10.1.1.2
        ip_prot: start = 17, end = 17                    <-- protocol 17 is UDP 
        l4_src: start = 1000, end = 1000                 <-- matches eq 1000 (equal UDP port 1000)

Policy information on the CG ID, as well as what interfaces use the CG ID.

9500H#show platform software fed active acl policy 9      <-- Use the CG ID value 
########################################################
#########                             ##################
########     Printing Policy Infos     #################
#########                             ##################
########################################################

INTERFACE: TwentyFiveGigE1/0/1                            <-- Interface with ACL applied 
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7f8cfc02de98
    Interface handle: 0x7e000028
    Interface Type: Port 
    if-id: 0x0000000000000008                             <-- The Interface IF_ID 0x8 
------------
Direction: Input                                          <-- ACl is applied in the ingress direction 
Protocol Type:IPv4                                        <-- Type is IPv4 
    Policy Intface Handle: 0x880000c1
    Policy Handle: 0x5b000093

########################################################
#########                             ##################
########      Policy information       #################
#########                             ##################
########################################################
Policy handle      : 0x5b000093
Policy name        : TEST                                 <-- ACL Name TEST
ID                 : 9                                    <-- CG ID for this ACL entry 
Protocol           : [3] IPV4
Feature            : [1] AAL_FEATURE_PACL                 <-- ASIC feature is PACL 
Number of ACLs     : 1

########################################################
## Complete policy ACL information
########################################################
Acl number    : 1
=====================================
Acl handle      : 0x320000d2
Acl flags       : 0x00000001
Number of ACEs  : 3                                       <-- 3 ACEs: two explicit and the implicit deny entry 
  Ace handle [1] : 0xb700010a
  Ace handle [2] : 0x5800010b 

Interface(s):
        TwentyFiveGigE1/0/1                               <-- The interface ACL is applied 
########################################################
#########                             ##################
########  Policy instance information  #################
#########                             ##################
########################################################
Policy intf handle    : 0x880000c1
Policy handle         : 0x5b000093
ID                    : 9
Protocol              : [3] IPV4
Feature               : [1] AAL_FEATURE_PACL
Direction             : [1] Ingress
Number of ACLs        : 1
Number of VMRs        : 3------------

Confirm PACL is working.

Note: When you enter the show ip access-lists privileged EXEC command, the match count displayed does not account for packets that are access controlled in hardware. Use the show platform software fed switch {switch_num|active|standby}acl counters hardware privileged EXEC command in order to obtain some basic hardware ACL statistics for switched and routed packets.

### Ping originated from neighbor device with source 10.1.1.1 ###
C9300#ping 10.1.1.2 source g 1/0/1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.1                        <--- Ping source is permitted and ping is successful 
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms <-- 100% ping success 


### Ping originated from neighbor device with source 10.1.1.3 ###
C9300#ping 10.1.1.2 source g 1/0/1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.3                        <-- Ping source is denied (implicit) and ping fails 
.....
Success rate is 0 percent (0/5)                                      <-- 0% ping success 


### Confirm PACL drop ###
9500H#show access-lists TEST
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any                                   <-- Counters in this command do not show matches
    20 permit udp host 10.1.1.1 eq 1000 host 10.1.1.2

9500H#show platform software fed active acl counters hardware | i PACL Drop
Ingress IPv4 PACL Drop            (0x77000005):         11 frames    <-- Hardware level command displays drops against PACL 
Ingress IPv6 PACL Drop            (0x12000012):          0 frames
<...snip...>

Scenario 2. PACL (MAC ACL)

PACLs are assigned to a Layer 2 interface.

• Security Boundary: Ports or VLANs
• Attachment: Layer 2 Interface
• Direction: Ingress or Egress (one at a time)
• Supported ACL Types: MAC ACL & IP ACLs (standard or extended)

Configure PACL with MAC ACL

9500H#show run | sec mac access-list
mac access-list extended MAC-TEST           <-- MAC ACL named MAC-TEST           
 permit host 0001.aaaa.aaaa any             <-- permit host MAC to any dest MAC 

9500H#show access-lists MAC-TEST
Extended MAC access list MAC-TEST
    permit host 0001.aaaa.aaaa any

9500H#show running-config interface twentyFiveGigE 1/0/1
Building configuration...

interface TwentyFiveGigE1/0/1
switchport access vlan 10
switchport mode access
mac access-group MAC-TEST in                <-- Applied MACL to layer 2 interface 

Verify PACL

Retrieve the IF_ID associated with the interface.

9500H#show platform software fed active ifm interfaces ethernet
Interface                         IF_ID               State 
----------------------------------------------------------------
TwentyFiveGigE1/0/1               0x00000008          READY     <-- IF_ID value for Tw1/0/1

Verify the Class group ID (CG ID) bound to the IF_ID.

9500H#show platform software fed active acl interface 0x8       <-- IF_ID with leading zeros omitted 
########################################################
########                              ##################
#######   Printing Interface Infos     #################
########                              ##################
########################################################

INTERFACE: TwentyFiveGigE1/0/1                                 <-- Confirms the interface matches the IF_ID 
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7f489404e408
    Interface handle: 0x7e000028
    Interface Type: Port                                       <-- Type: Port indicates Layer 2 interface 
    if-id: 0x0000000000000008                                  <-- IF_ID 0x8 is correct 
    Input MAC: Policy Handle: 0xde000098 
        Policy Name: MAC-TEST                                  <-- The named ACL bound to this interface 
             CG ID: 20                                         <-- Class Group ID for this entry 
       CGM Feature: [0] acl                                    <-- Feature is ACL 
        Bind Order: 0

ACL information associated with the CG ID.

9500H#show platform software fed active acl info acl-cgid 20  <-- The CG ID associated to the ACl MAC-TEST
########################################################
#########                             ##################
########      Printing CG Entries      #################
#########                             ##################
########################################################
===================================
ACL CG (acl/20): MAC-TEST type: MAC                           <-- feature ACL/CG ID 20: ACL name MAC-TEST : type MAC ACL 
Total Ref count 1
---------------------------------
1 Interface                                                   <-- Applied to one interface 
---------------------------------
  region reg_id: 3
    subregion subr_id: 0
       GCE#:1 #flds: 2 l4:N matchall:N deny:N
         Result: 0x01010000
         mac_dest: value = 0x00, mask = 0x00                  <-- Mac dest: hex 0x00 mask 0x00 is "any destination 
         mac_src: value = 0x1aaaaaaaa, mask = 0xffffffffffff  
<-- Mac source: 0x1aaaaaaaa | hex with leading zeros omitted (0001.aaaa.aaaa) & mask 0xffffffffffff is host exact match 

Policy information on the CG ID, as well as what interfaces use the CG ID.

9500H#show platform software fed active acl policy 20      <-- Use the CG ID value 
########################################################
#########                             ##################
########     Printing Policy Infos     #################
#########                             ##################
########################################################

INTERFACE: TwentyFiveGigE1/0/1                            <-- Interface with ACL applied 
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7f8cfc02de98
    Interface handle: 0x7e000028
    Interface Type: Port 
    if-id: 0x0000000000000008                             <-- The Interface IF_ID 0x8 
------------
Direction:  Input                                         <-- ACl is applied in the ingress direction 
Protocol Type:MAC                                         <-- Type is MAC
    Policy Intface Handle: 0x30000c6
    Policy Handle: 0xde000098

########################################################
#########                             ##################
########         Policy information    #################
#########                             ##################
########################################################
Policy handle         : 0xde000098
Policy name           : MAC-TEST                          <-- ACL name is MAC-TEST
ID                    : 20                                <-- CG ID for this ACL entry
Protocol              : [1] MAC
Feature               : [1] AAL_FEATURE_PACL              <-- ASIC Feature is PACL 
Number of ACLs        : 1

########################################################
## Complete policy ACL information
########################################################
Acl number : 1
=====================================
Acl handle : 0xd60000dc
Acl flags : 0x00000001
Number of ACEs : 2                                        <-- 2 ACEs: one permit, and one implicit deny 
  Ace handle [1] : 0x38000120
  Ace handle [2] : 0x31000121

Interface(s):
        TwentyFiveGigE1/0/1                               <-- Interface the ACL is applied 
########################################################
#########                             ##################
########  Policy instance information  #################
#########                             ##################
########################################################
Policy intf handle    : 0x030000c6
Policy handle         : 0xde000098
ID                    : 20
Protocol              : [1] MAC
Feature               : [1] AAL_FEATURE_PACL
Direction             : [1] Ingress
Number of ACLs        : 1
Number of VMRs        : 3------------

Confirm PACL is working:

• The MACL only permits source address 0001.aaaa.aaaa.
• Since this is a MAC ACL, a non-IP ARP packet is dropped and thereby causing the ping to fail.

### Ping originated from neighbor device with Source MAC 0000.0000.0002 ###
C9300#ping 10.1.1.2 source vlan 10
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.1
.....
Success rate is 0 percent (0/5)

C9300#show ip arp
Protocol  Address          Age (min)  Hardware Addr    Type    Interface
Internet  10.1.1.2                0   Incomplete       ARPA                <-- ARP is unable to complete on Source device

### Monitor capture configured on Tw 1/0/1 ingress ###
9500H#monitor capture 1 interface TwentyFiveGigE 1/0/1 in match any

9500H#show monitor cap
Status Information for Capture 1
  Target Type:
 Interface: TwentyFiveGigE1/0/1, Direction: IN  


9500H#sh monitor capture 1 buffer brief | inc ARP
    5   4.767385 00:00:00:00:00:02 b^F^R ff:ff:ff:ff:ff:ff ARP 60 Who has 10.1.1.2? Tell 10.1.1.1
    8   8.767085 00:00:00:00:00:02 b^F^R ff:ff:ff:ff:ff:ff ARP 60 Who has 10.1.1.2? Tell 10.1.1.1
   11  10.767452 00:00:00:00:00:02 b^F^R ff:ff:ff:ff:ff:ff ARP 60 Who has 10.1.1.2? Tell 10.1.1.1
   13  12.768125 00:00:00:00:00:02 b^F^R ff:ff:ff:ff:ff:ff ARP 60 Who has 10.1.1.2? Tell 10.1.1.1
<-- 9300 (10.1.1.1) sends ARP request, but since there is no reply 4 more ARP requests are sent 


9500H#show platform software fed active acl counters hardware | inc MAC PACL Drop
Ingress MAC PACL Drop                       (0x73000021): 937 frames         <-- Confirmed that ARP requests are dropped from Ingress MAC filter
Egress MAC PACL Drop                        (0x0200004c): 0 frames
<...snip...>

Scenario 3. RACL

RACL is assigned to a Layer 3 interface such as an SVI or Routed interface.

• Security Boundary: Different Subnets
• Attachment: Layer 3 Interface
• Direction: Ingress or Egress
• Supported ACL Types: IP ACLs (standard or extended)

Configure RACL

9500H(config)#ip access-list extended TEST          <-- Create a named extended ACL
9500H(config-ext-nacl)#permit ip host 10.1.1.1 any
9500H(config-ext-nacl)#permit udp host 10.1.1.1 eq 1000 host 10.1.1.2

9500H#show access-lists TEST                        <-- Display the ACL configured 
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any
    20 permit udp host 10.1.1.1 eq 1000 host 10.1.1.2

9500H(config)#interface Vlan 10                     <-- Apply ACL to Layer 3 SVI interface  
9500H(config-if)#ip access-group TEST in

9500H#show running-config interface Vlan 10
Building configuration...

Current configuration : 84 bytes
!
interface Vlan10
 ip access-group TEST in                            <-- Display the ACL applied to the interface 
end

Verify RACL

Retrieve the IF_ID associated with the interface.

9500H#show platform software fed active ifm mappings l3if-le  <-- Retrieve the IF_ID for a Layer 3 SVI type port 
Mappings Table

L3IF_LE                   Interface                            IF_ID             Type
----------------------------------------------------------------------------------------------------
0x00007f8d04983958        Vlan10                               0x00000026        SVI_L3_LE        <-- IF_ID value for SVI 10

Verify the Class group ID (CG ID) bound to the IF_ID.

9500H#show platform software fed active acl interface 0x26  <-- IF_ID for SVI Vlan 10 with leading zeros omitted 
########################################################
########                              ##################
#######     Printing Interface Infos   #################
########                              ##################
########################################################

INTERFACE: Vlan10                                           <-- Confirms the interface matches the IF_ID
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7f8cfc02de98
    Interface handle: 0x6e000047
    Interface Type: L3                                      <-- Type: L3 indicates Layer 3 type interface 
    if-id: 0x0000000000000026                               <-- IF_ID 0x26 is correct       
    Input IPv4: Policy Handle: 0x2e000095
        Policy Name: TEST                                   <-- The named ACL bound to this interface                                   
             CG ID: 9                                       <-- Class Group ID for this entry 
       CGM Feature: [0] acl                                 <-- Feature is ACL 
        Bind Order: 0

ACL information associated with the CG ID.

9500H#show platform software fed active acl info acl-cgid 9  <-- The CG ID associated to the ACL TEST
########################################################
#########                             ##################
########      Printing CG Entries      #################
#########                             ##################
########################################################
===================================
ACL CG (acl/9): TEST type: IPv4        <-- feature ACL/CG ID 9: ACl name TEST : ACl type IPv4 
Total Ref count 2
---------------------------------
2 Interface                            <-- Interface count is 2. Applied to SVI 10 and as PACL to Tw1/0/1
---------------------------------
region reg_id: 10
  subregion subr_id: 0
    GCE#:1 #flds: 2 l4:N matchall:N deny:N            <-- #flds: 2 = two fields in entry | l4:N (no Layer 4 port match) 
      Result: 0x01010000
      ipv4_src: value = 0x0a010101, mask = 0xffffffff <-- src 0x0a010101 hex = 10.1.1.1 | mask 0xffffffff = exact host match
      ipv4_dst: value = 0x00000000, mask = 0x00000000 <-- dst & mask = 0x00000000 = match any
    GCE#:1 #flds: 4 l4:Y matchall:N deny:N            <-- #flds: 4 = four fields in entry | l4:Y (ACE uses UDP port L4 match)
      Result: 0x01010000
      ipv4_src: value = 0x0a010101, mask = 0xffffffff <-- Exact match (host) 10.1.1.1 
      ipv4_dst: value = 0x0a010102, mask = 0xffffffff <-- Exact match (host) 10.1.1.2
      ip_prot: start = 17, end = 17                   <-- protocol 17 is UDP 
      l4_src: start = 1000, end = 1000                <-- matches eq 1000 (equal UDP port 1000)

Policy information on the CG ID, as well as what interfaces use the CG ID.

9500H#show platform software fed active acl policy 9      <-- Use the CG ID Value 
########################################################
#########                             ##################
########     Printing Policy Infos     #################
#########                             ##################
########################################################

INTERFACE: Vlan10                                         <-- Interface with ACL applied 
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7f8cfc02de98
    Interface handle: 0x6e000047
    Interface Type: L3
    if-id: 0x0000000000000026                             <-- Interface IF_ID 0x26
------------
Direction:  Input                                         <-- ACL applied in the ingress direction 
Protocol Type:IPv4                                        <-- Type is IPv4 
    Policy Intface Handle: 0x1c0000c2
    Policy Handle: 0x2e000095


########################################################
#########                             ##################
########        Policy information     #################
#########                             ##################
########################################################
Policy handle        : 0x2e000095
Policy name          : TEST                               <-- ACL name TEST
ID                   : 9                                  <-- CG ID for this ACL entry 
Protocol             : [3] IPV4
Feature              : [27] AAL_FEATURE_RACL              <-- ASIC feature is RACL 
Number of ACLs       : 1

########################################################
## Complete policy ACL information
########################################################
Acl number       : 1
=====================================
Acl handle         : 0x7c0000d4
Acl flags          : 0x00000001
Number of ACEs     : 5                                    <-- 5 Aces: 2 explicit, 1 implicit deny, 2 ??? CHECK this 
  Ace handle [1] : 0x0600010f
  Ace handle [2] : 0x8e000110
  Ace handle [3] : 0x3b000111
  Ace handle [4] : 0xeb000112
  Ace handle [5] : 0x79000113

Interface(s):
        Vlan10                                            <-- The interface the ACL is applied 
########################################################
#########                             ##################
########  Policy instance information  #################
#########                             ##################
########################################################
Policy intf handle     : 0x1c0000c2
Policy handle          : 0x2e000095
ID                     : 9
Protocol               : [3] IPV4
Feature                : [27] AAL_FEATURE_RACL
Direction              : [1] Ingress
Number of ACLs         : 1
Number of VMRs         : 4------------

Confirm RACL is working.

Note: When you enter the show ip access-lists privileged EXEC command, the match count displayed does not account for packets that are access controlled in hardware. Use the show platform software fed switch{switch_num|active|standby}acl counters hardwareprivileged EXEC command in order to obtain some basic hardware ACL statistics for switched and routed packets.

### Ping originated from neighbor device with source 10.1.1.1 ###
C9300#ping 10.1.1.2 source g 1/0/1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.1                        <--- Ping source is permitted and ping is successful 
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms <-- 100% ping success 


### Ping originated from neighbor device with source 10.1.1.3 ###
C9300#ping 10.1.1.2 source g 1/0/1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.3                        <-- Ping source is denied (implicit) and ping fails 
.....
Success rate is 0 percent (0/5)                                      <-- 0% ping success 


### Confirm RACL drop ###
9500H#show access-lists TEST
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any                                   <-- Counters in this command do not show matches
    20 permit udp host 10.1.1.1 eq 1000 host 10.1.1.2

9500H#show platform software fed active acl counters hardware | i RACL Drop
Ingress IPv4 RACL Drop              (0xed000007):         100 frames  <-- Hardware level command displays drops against RACL 
<...snip...>

Scenario 4. VACL

VACLs are assigned to a Layer 2 VLAN. 

• Security Boundary: Within OR across a VLAN
• Attachment: VLAN/VLAN Map
• Direction: Both Ingress and Egress at once
• Supported ACL Types: MAC ACL & IP ACLs (standard or extended)

Configure VACL

ip access-list extended TEST
 10 permit ip host 10.1.1.1 any
 20 permit ip any host 10.1.1.1

ip access-list extended ELSE
 10 permit ip any any

vlan access-map VACL 10
 match ip address TEST
 action forward
vlan access-map VACL 20
 match ip address ELSE
 action drop

vlan filter VACL vlan-list 10


9500H#sh vlan access-map VACL
Vlan access-map "VACL" 10
  Match clauses:
    ip address: TEST
  Action:
    forward
Vlan access-map "VACL" 20
  Match clauses:
    ip address: ELSE
  Action:
    drop

9500H#sh vlan filter access-map VACL
VLAN Map VACL is filtering VLANs:
10

Verify VACL

Retrieve the IF_ID associated with the interface.

9500H#show platform software fed active ifm interfaces vlan
Interface                         IF_ID               State
----------------------------------------------------------------------
Vlan10                            0x00420010          READY

Verify the Class group ID (CG ID) bound to the IF_ID.

9500H#show platform software fed active acl interface 0x420010  <-- IF_ID for the Vlan 
########################################################
########                              ##################
#######   Printing Interface Infos     #################
########                              ##################
########################################################

INTERFACE: Vlan10                                               <-- Can be L2 only, with no vlan interface 
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7fc8cc7c7f48
    Interface handle: 0xf1000024
    Interface Type: Vlan
    if-id: 0x0000000000420010
    Input IPv4: Policy Handle: 0xd10000a3                       <-- VACL has both Ingress and Egress actions 
        Policy Name: VACL                                       <-- Name of the VACL used 
             CG ID: 530                                         <-- Class Group ID for entry 
       CGM Feature: [35] acl-grp                                <-- Feature is ACL group, versus ACl
        Bind Order: 0

    Output IPv4: Policy Handle: 0xc80000a4                      <-- VACL has both Ingress and Egress actions
         Policy Name: VACL
              CG ID: 530
         CGM Feature: [35] acl-grp
    Bind Order: 0

ACL information associated with the CG Group ID.

There are two ACLs used in the same named VACL policy, grouped into this acl-group

9500H#show platform software fed active acl info acl-grp-cgid 530  <-- use the group-id command versus gc ID
########################################################
#########                             ##################
########    Printing CG Entries        #################
#########                             ##################
########################################################
===================================
ACL CG (acl-grp/530): VACL type: IPv4                              <-- feature acl/group ID 530: name VACL : type IPv4
Total Ref count 2
---------------------------------
2 VACL                                                             <-- Ingress and egress ACL direction on a VACl 
---------------------------------
  region reg_id: 12
    subregion subr_id: 0
      GCE#:10 #flds: 2 l4:N matchall:N deny:N
        Result: 0x06000000
        ipv4_src: value = 0x0a010101, mask = 0xffffffff           <-- permit from host 10.1.1.1 (see PACL example for hex conversion)
        ipv4_dst: value = 0x00000000, mask = 0x00000000           <-- to any other host
      GCE#:20 #flds: 2 l4:N matchall:N deny:N
        Result: 0x06000000
        ipv4_src: value = 0x00000000, mask = 0x00000000           <-- permit from any host 
        ipv4_dst: value = 0x0a010101, mask = 0xffffffff           <-- to host 10.1.1.1
      GCE#:10 #flds: 2 l4:N matchall:N deny:N
        Result: 0x05000000
        ipv4_src: value = 0x00000000, mask = 0x00000000           <-- This is the ACL named 'ELSE' which is permit any any
        ipv4_dst: value = 0x00000000, mask = 0x00000000           <-- with VACL, the logic used was "permit to match" action "drop"

Policy information on the CG ID, as well as what interfaces use the CG ID.

9500H#show platform software fed active acl policy 530     <-- use the acl-grp ID 
########################################################
#########                             ##################
########     Printing Policy Infos     #################
#########                             ##################
########################################################

INTERFACE: Vlan10
MAC 0000.0000.0000
########################################################
    intfinfo: 0x7fa15802a5d8
    Interface handle: 0xf1000024
    Interface Type: Vlan                                   <-- Interface type is the Vlan, not a specific interface 
    if-id: 0x0000000000420010                              <-- the Vlan IF_ID matches Vlan 10
------------
Direction: Input                                           <-- VACL in the input direction
Protocol Type:IPv4
    Policy Intface Handle: 0x44000001
    Policy Handle: 0x29000090

########################################################
#########                             ##################
########       Policy information      #################
#########                             ##################
########################################################
Policy handle       : 0x29000090
Policy name         : VACL                                 <-- the VACL policy is named 'VACL'
ID                  : 530
Protocol            : [3] IPV4
Feature             : [23] AAL_FEATURE_VACL                <-- ASIC feature is VACL 
Number of ACLs      : 2                                    <-- 2 ACL used in the VACL: "TEST & ELSE"

########################################################
## Complete policy ACL information
########################################################
Acl number : 1
=====================================
Acl handle : 0xa6000090
Acl flags : 0x00000001
Number of ACEs : 4
  Ace handle [1] : 0x87000107
  Ace handle [2] : 0x30000108
  Ace handle [3] : 0x73000109
  Ace handle [4] : 0xb700010a

Acl number : 2
=====================================
Acl handle : 0x0f000091
Acl flags : 0x00000001
Number of ACEs : 1
  Ace handle [1] : 0x5800010b

Interface(s):
        Vlan10
########################################################
#########                             ##################
########  Policy instance information  #################
#########                             ##################
########################################################
Policy intf handle    : 0x44000001
Policy handle         : 0x29000090
ID                    : 530                                <-- 530 is the acl group ID
Protocol              : [3] IPV4
Feature               : [23] AAL_FEATURE_VACL
Direction             : [1] Ingress                        <-- Ingress VACL direction 
Number of ACLs        : 2
Number of VMRs        : 4------------
Direction:  Output
Protocol Type:IPv4
    Policy Intface Handle: 0xac000002
    Policy Handle: 0x31000091

########################################################
#########                             ##################
########        Policy information     #################
#########                             ##################
########################################################
Policy handle        : 0x31000091
Policy name          : VACL
ID                   : 530
Protocol             : [3] IPV4
Feature              : [23] AAL_FEATURE_VACL
Number of ACLs       : 2

########################################################
## Complete policy ACL information
########################################################
Acl number    : 1
=====================================
Acl handle      : 0xe0000092
Acl flags       : 0x00000001
Number of ACEs  : 4
  Ace handle [1] : 0xf500010c
  Ace handle [2] : 0xd800010d
  Ace handle [3] : 0x4c00010e
  Ace handle [4] : 0x0600010f

Acl number    : 2
=====================================
Acl handle      : 0x14000093
Acl flags       : 0x00000001
Number of ACEs : 1
  Ace handle [1] : 0x8e000110

Interface(s):
        Vlan10
########################################################
#########                             ##################
########  Policy instance information  #################
#########                             ##################
########################################################
Policy intf handle    : 0xac000002
Policy handle         : 0x31000091
ID                    : 530                               <-- 530 is the acl group ID
Protocol              : [3] IPV4
Feature               : [23] AAL_FEATURE_VACL
Direction             : [2] Egress                        <-- Egress VACL direction 
Number of ACLs        : 2
Number of VMRs        : 4------------

Confirm VACL is working.

• Troubleshoot is the same scenario as PACL and RACl sections. Refer to these sections for details on the ping test.
• Ping from 10.1.1.3 to 10.1.1.2 denied by the ACL policy applied. 
• Check the platform drop command.

9500H#show platform software fed active acl counters hardware | inc VACL Drop
Ingress IPv4 VACL Drop              (0x23000006):         1011 frames      <-- Hardware level command displays drops against VACL 
<...snip...>

Scenario 5. Group/Client ACL (DACL)

Group/Client ACLs are applied dynamically to a user group or client based on their identity. These are also sometimes called DACL.

• Security Boundary: Client (Client interface level)
• Attachment: Per client interface
• Direction: Ingress only
• Supported ACL Types: MAC ACL and IP ACLs (standard or extended)

Configure GACL

Cat9400#show run interface gigabitEthernet 2/0/1 
Building configuration...

Current configuration : 419 bytes
!
interface GigabitEthernet2/0/1
 switchport access vlan 10
 switchport mode access
 switchport voice vlan 5
 ip access-group ACL-ALLOW in                     <-- This is the pre-authenticated ACL (deny ip any any). Validation is done for the post-auth ACL
 authentication periodic
 authentication timer reauthenticate server
 access-session control-direction in
 access-session port-control auto
 no snmp trap link-status
 mab
 dot1x pae authenticator
 spanning-tree portfast
 service-policy type control subscriber ISE_Gi2/0/1
end

Cat9400#show access-session interface gigabitEthernet 2/0/1 details 
            Interface:  GigabitEthernet2/0/1
               IIF-ID:  0x1765EB2C                <-- The IF_ID used in this example is dynamic 
          MAC Address:  000a.aaaa.aaaa            <-- The client MAC
         IPv6 Address:  Unknown
         IPv4 Address:  10.10.10.10
            User-Name:  00-0A-AA-AA-AA-AA
               Status:  Authorized                <-- Authorized client
               Domain:  VOICE
       Oper host mode:  multi-auth
     Oper control dir:  in
      Session timeout:  300s (server), Remaining: 182s
       Timeout action:  Reauthenticate
    Common Session ID:  27B17A0A000003F499620261
      Acct Session ID:  0x000003e7
               Handle:  0x590003ea
       Current Policy:  ISE_Gi2/0/1


Server Policies:
              ACS ACL:  xACSACLx-IP-MAB-FULL-ACCESS-59fb6e5e  <-- The ACL pushed from ISE server 


Method status list:
       Method           State
        dot1x           Stopped
          mab           Authc Success                                      <-- Authenticated via MAB (Mac authentication bypass)

Cat9400#show ip access-lists xACSACLx-IP-MAB-FULL-ACCESS-59fb6e5e
Extended IP access list xACSACLx-IP-MAB-FULL-ACCESS-GOOD-59fb6e5e
    1 permit ip any any                                                   <-- ISE pushed a permit ip any any 

Verify GACL

Group CG ID bound to the iif-id.

Cat9400#show platform software fed active acl interface 0x1765EB2C                 <-- The IF_ID from the access-session output
########################################################
########                              ##################
#######    Printing Interface Infos    #################
########                              ##################
########################################################

INTERFACE: Client MAC 000a.aaaa.aaaa                                              <-- Client MAC matches the access-session output
MAC 000a.aaaa.aaaa
########################################################
    intfinfo: 0x7f104820cae8
    Interface handle: 0x5a000110
    Interface Type: Group                                                          <-- This is a group identity type policy 
    IIF ID: 0x1765eb2c                                             
    Input IPv4: Policy Handle: 0x9d00011e
        Policy Name: ACL-ALLOW:xACSACLx-IP-MAB-FULL-ACCESS-59fb6e5e: <-- DACL name matches 
             CG ID: 127760                                                         <-- The ACL group ID                     
       CGM Feature: [35] acl-grp 
        Bind Order: 0

ACL information associated with the group GC ID.

Cat9400#show platform software fed active acl info acl-grp-cgid 127760                            <-- the CG ID for this DACL 
########################################################
#########                             ##################
########      Printing CG Entries      #################
#########                             ##################
########################################################
===================================
ACL CG (acl-grp/127760): ACL-ALLOW:xACSACLx-IP-MAB-FULL-ACCESS-59fb6e5e: type: IPv4  <-- Group ID & ACL name are correct 
Total Ref count 1
---------------------------------
1 CGACL                                                                                            <-- 1  GACL (group ACL) is applied 
---------------------------------
  region reg_id: 1
    subregion subr_id: 0
      GCE#:1 #flds: 2 l4:N matchall:N deny:N
        Result: 0x04000000
        ipv4_src: value = 0x00000000, mask = 0x00000000                                           <-- Permits IP any any as seen in software 
        ipv4_dst: value = 0x00000000, mask = 0x00000000
      GCE#:10 #flds: 2 l4:N matchall:N deny:N
        Result: 0x04000000
        ipv4_src: value = 0x00000000, mask = 0x00000000
        ipv4_dst: value = 0x00000000, mask = 0x00000000

Scenario 6. ACL Logging

The device software can provide syslog messages about packets permitted or denied by a standard IP access list. Any packet that matches the ACL causes an informational log message about the packet to be sent to the console. The level of messages logged to the console is controlled by thelogging consolecommands controlling the Syslog messages.

• ACL log messages are not supported for ACLs used with Unicast Reverse Path Forwarding (uRPF). It is only supported for RACL.

• ACL log in the egress direction is not supported for packets that are generated from the control plane of the device.

• Routing is done in hardware and logging in software, so if a large number of packets match a permit or deny ACE containing a logkeyword, the software is unable to match the hardware processing rate, and not all packets can be logged.
• The first packet that triggers the ACL causes a log message right away, and subsequent packets are collected over 5-minute intervals before they appear or are logged. The log message includes the access list number, whether the packet was permitted or denied, the source IP address of the packet, and the number of packets from that source permitted or denied in the prior 5-minute interval.
• See the appropriate Security Configuration Guide, Cisco IOS XE as noted in the Related Information section for complete details on ACL log behavior and restrictions.

Log Example PACL:

This example shows a negative case, where the ACL type and log keyword do not work together.

9500H#show access-lists TEST
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any log             <-- Log keyword applied to ACE entry 
    20 deny ip host 10.1.1.3 any log 

9500H(config)#interface twentyFiveGigE 1/0/1
9500H(config-if)#ip access-group TEST in           <-- apply logged ACL 
Switch Port ACLs are not supported for LOG!        <-- message indicates this is an unsupported combination 

Log Example RACL (Deny):

9500H#show access-lists TEST
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any log            <-- Log keyword applied to ACE entry 
    20 deny ip host 10.1.1.3 any log 

9500H(config)#interface vlan 10
9500H(config-if)#ip access-group TEST in          <-- ACL applied to SVI

### Orginate ICMP from 10.1.1.3 to 10.1.1.2 (denied by ACE) ###
C9300#ping 10.1.1.2 source vlan 10 repeat 110
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.3
..........
Success rate is 0 percent (0/110)

9500H#show access-list TEST
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any log
    20 deny ip host 10.1.1.3 any log (110 matches)  <-- Matches increment in show access-list command 

9500H#show platform software fed active acl counters hardware | inc RACL
Ingress IPv4 RACL Drop          (0xed000007):            0 frames
Ingress IPv4 RACL Drop and Log  (0x93000009):          110 frames   <-- Aggregate command shows hits on the RACL Drop and Log 

%SEC-6-IPACCESSLOGDP: list TEST denied icmp 10.1.1.3 -> 10.1.1.2 (8/0), 10 packets  <-- Syslog message is produced 

Log Example RACL (Permit):
When a log statement is used for a permit statement, the software counter hits show double the number of packets sent.

C9300#ping 10.1.1.2 source vlan 10 repeat 5          <-- 5 ICMP Requests are sent 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
Packet sent with a source address of 10.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

9500H#show access-lists TEST
Extended IP access list TEST
    10 permit ip host 10.1.1.1 any log (10 matches)  <-- Hit counter shows 10 
    20 deny ip host 10.1.1.3 any log (115 matches)

Troubleshoot

ACL Statistics

When you troubleshoot an ACL issue, it is essential to understand how and where ACL statistics are measured by the device.  

• ACL Statistics are collected at an aggregate level, and not per ACE level.
• Hardware does not have the capability to allow per ACE or per ACL stats.
• Statistics such as Deny, Log, and CPU forwarded packets are collected.
• Statistics for MAC, IPv4, and IPv6 packets are collected separately.
• show platform software fed switch active acl counters hardware  can be used in order to display aggregate statistics.

Clearing ACL Statistics

When troubleshooting an ACL issue, it can be helpful to clear the various ACL counters in order to get fresh baseline counts.

• These commands allow you to clear software and hardware ACL counter statistics.
• When you troubleshoot ACL match/hit events, it is recommended to clear the relevant ACL to baseline matches that are recent or relevant.

clear platform software fed active acl counters hardware (clears the hardware matched counters)
clear ip access-list counters <acl_name> (clears the software matched counters - IPv4)
clear ipv6 access-list counters <acl_name> (clears the software matched counters - IPv6)

What happens when ACL TCAM is exhausted?

• ACLs are always applied in hardware TCAM. If TCAM is already used by previously configured ACLs, the new ACLs do not get the required ACL resources needed to program.

• If an ACL is added after TCAM is exhausted, all packets are dropped for the interface it is attached.

• The action of holding an ACL in software is called Unloading.
• When resources become available, the switch automatically tries to program the ACLs into the hardware. If successful, the ACLs are pushed to hardware and packets start to forward.
• The action of programming a software-held ACL into TCAM is called Reloading.

• PACL, VACL, RACL, and GACL can be unloaded/reloaded independently of each other.

ACL TCAM Exhaustion

• The interface to which the newly added ACL is applied starts dropping packets until hardware resources become available.
• GACL clients are put into the UnAuth state.

VCU Exhaustion

• Once over the L4OPs limit or out of VCUs, the software performs ACL expansion and creates new ACE entries in order to perform equivalent action without using VCUs.
• Once this happens TCAM can become exhausted from these added entries.

ACL Syslog Errors

If you run out of a particular Security ACL resource, SYSLOG messages are generated by the system (interface, VLAN, label, and so on, values can differ).

Out of Resource Scenarios and Recovery Actions

Verify ACL Scale

This section covers commands in order to determine the ACL scale and TCAM utilization.

FMAN Access-list Summary:

Identify configured ACLs and total ACE count per ACL.

9500H#show platform software access-list f0 summary
Access-list                          Index        Num Ref        Num ACEs
--------------------------------------------------------------------------
TEST                                 1            1              2        <-- ACL TEST contains 2 ACE entries 
ELSE                                 2            1              1
DENY                                 3            0              1

ACL Usage:

9500H#show platform software fed active acl usage
########################################################
########                              ##################
#######      Printing Usage Infos      #################
########                              ##################
########################################################
##### ACE Software VMR max:196608 used:283                   <-- Value/Mask/Result entry usage 
########################################################
==================================================================================================
Feature Type           ACL Type        Dir              Name                    Entries Used
VACL                   IPV4            Ingress          VACL                    4
<-- Type of ACL Feature, type of ACL, Direction ACL applied, name of ACL, and number of TCAM entries consumed 
==================================================================================================
Feature Type           ACL Type        Dir             Name                     Entries Used
RACL                   IPV4            Ingress         TEST                     5

TCAM Usage (17.x):

TCAM usage command has significant differences between 16.x and 17.x trains.

9500H#show platform hardware fed active fwd-asic resource tcam utilization
Codes: EM - Exact_Match, I - Input, O - Output, IO - Input & Output, NA - Not Applicable

CAM Utilization for ASIC [0]
 Table                   Subtype     Dir      Max     Used    %Used       V4       V6    MPLS   Other
 ------------------------------------------------------------------------------------------------------
 Security ACL Ipv4       TCAM        I        7168       16    0.22%       16        0       0        0
 Security ACL Non Ipv4   TCAM        I        5120       76    1.48%        0       36       0       40
 Security ACL Ipv4       TCAM        O        7168       18    0.25%       18        0       0        0
 Security ACL Non Ipv4   TCAM        O        8192       27    0.33%        0       22       0        5
<...snip...>

<-- Percentage used and other counters about ACL consumption 
<-- Dir = ACL direction (Input/Output ACl)

TCAM Usage (16.x):

TCAM usage command has significant differences between 16.x and 17.x trains.

C9300#show platform hardware fed switch active fwd-asic resource tcam utilization
CAM Utilization for ASIC [0]
 Table                                               Max Values      Used Values
--------------------------------------------------------------------------------
 Security Access Control Entries                       5120          126         <-- Total used of the Maximum 
<...snip...>

Custom SDM Template (TCAM Reallocation)

Using Cisco IOS XE Bengaluru 17.4.1, you can configure a custom SDM template for ACL features using the sdm prefer custom aclcommand.

9500H#show sdm prefer
Showing SDM Template Info

This is the Core template.                                                                   <-- Core SDM template in use 
  Security Ingress IPv4 Access Control Entries*:         7168  (current) - 7168  (proposed)  <-- IPv4 ACL maximum TCAM available
  Security Ingress Non-IPv4 Access Control Entries*:     5120  (current) - 5120  (proposed)
  Security Egress IPv4 Access Control Entries*:          7168  (current) - 7168  (proposed)
  Security Egress Non-IPv4 Access Control Entries*:      8192  (current) - 8192  (proposed)
  <...snip...>

9500H#show sdm prefer custom user-input
Custom Template Feature Values are not modified                                              <-- No customization to SDM 

• 9500H(config)#sdm prefer custom acl
  9500H(config-sdm-acl)#acl-ingress 26 priority 1 <-- apply new 26K value. (priority discussed in the configuration guide)
  9500H(config-sdm-acl)#acl-egress 20 priority 2
  9500H(config-sdm-acl)#exit
  Use show sdm prefer custom in order to see the proposed values and sdm prefer custom commit in order to apply 'view the changes' via this CLI.
• Verify changes to the SDM profile.
• 9500H#show sdm prefer custom
  

Showing SDM Template Info:

This is the custom template with its details.
Ingress Security Access Control Entries*: 12288 (current) - 26624 ( proposed) <-- Current and proposed usage (26K proposed)
Egress Security Access Control Entries*: 15360 (current) - 20480 (proposed)


9500H#show sdm prefer custom user-input

ACL FEATURE USER INPUT
User Input values
==========================

FEATURE NAME PRIORITY SCALE
--------------------------------------------------------------------------
Ingress Security Access Control Entries: 1 26*1024 <-- Modifed by user input to 26 x 1024 (26K)
Egress Security Access Control Entries: 2 20*1024 <-- Modifed by user input to 20 x 1024 (20K)

• Apply changes to the SDM profile.
• 9500H(config)#sdm prefer custom commit
  Changes to the running SDM preferences are stored and take effect on the next reload. <-- Once reloaded, ACL TCAM allocated to custom value.

Further Reading:

ACL Processing Order:

ACLs are processed in this order from Source to Destination.

ACLs Programmed in a Stack:

• ACLs that are not port-based (for example, VACL, RACL) are applied to traffic on any switch and are programmed on all switches in the stack.

• Port-based ACLs are applied only to the traffic on a port and are programmed only on the switch that owns the interface.

• ACLs are programmed by the Active switch and subsequently applied to Member switches.

• The same rules apply to other redundancy options, such as ISSU/SVL.

ACL Expansion:

• ACL expansion happens when the device runs out of L4OPs, Lables, or VCUs. The device must create multiple equivalent ACEs in order to accomplish the same logic, and in order to rapidly exhaust TCAM.
• ### L4OPs are at scale and this ACL is created ##
  9500H(config)#ip access-list extended TEST
  9500H(config-ext-nacl)#permit tcp 10.0.0.0 0.255.255.255 any gt 150 <-- matches ports 151 and higher
  
  
  ### This must be expanded into mutiple ACEs that do not use an L4OP ###
  9500H(config-ext-nacl)#permit tcp 10.0.0.0 0.255.255.255 any eq 151
  9500H(config-ext-nacl)#permit tcp 10.0.0.0 0.255.255.255 any eq 152
  9500H(config-ext-nacl)#permit tcp 10.0.0.0 0.255.255.255 any eq 153
  9500H(config-ext-nacl)#permit tcp 10.0.0.0 0.255.255.255 any eq 154
  ... and so on ....

TCAM Consumption and Label Sharing:

• Each ACL policy is referenced internally by a label.

• When ACL policy (Security ACL like GACL, PACL, VACL, RACL) is applied to multiple interfaces or VLAN, it uses the same label.

• Ingress/Egress ACL uses different label spaces.

• IPv4, IPv6, and MAC ACL use other label spaces.

• The same PACL is applied to the ingress of interface-A and egress of interface-A. There are two instances of the PACL in the TCAM, each one with a unique label for Ingress and Egress.

• If the same PACL with an L4OP is applied to multiple ingress interfaces that exist on each core, there are two instances of the same PACL programmed in TCAM, one per each core.

VMR Description:

An ACE is internally programmed in TCAM as a 'VMR' – also known as Value, Mask, Result. Each ACE entry can consume VMRs and can consume VCUs.

ACL Scalability:

Security ACL Resources are dedicated to Security ACLs. They are not shared with other features.

Related Information

• Security Configuration Guide, Cisco IOS XE Amsterdam 17.3.x (Catalyst 9200 Switches)
• Security Configuration Guide, Cisco IOS XE Amsterdam 17.3.x (Catalyst 9300 Switches)
• Security Configuration Guide, Cisco IOS XE Amsterdam 17.3.x (Catalyst 9400 Switches)
• Security Configuration Guide, Cisco IOS XE Amsterdam 17.3.x (Catalyst 9500 Switches)
• Security Configuration Guide, Cisco IOS XE Amsterdam 17.3.x (Catalyst 9600 Switches)
• System Management Configuration Guide, Cisco IOS XE Bengaluru 17.4.x (Catalyst 9500 Switches)
• Cisco Technical Support & Downloads

Debug and Trace Commands