Displaying Acl Information; Displaying Acls - Cisco 2950 - Catalyst Switch Configuration Manual

Chapter 29 Configuring Network Security with ACLs
Command
Step 4 end
Step 5
show running-config
Step 6 copy running-config startup-config
This example shows how to apply access list 2 on an interface to filter packets entering the interface:
Switch(config)# interface gigabitethernet0/2
Router(config-if)# ip access-group 2 in
The ip access-group interface configuration command is only valid when applied to a management
Note
interface or a Layer 2 physical interface. ACLs cannot be applied to interface port-channels.
For inbound ACLs, after receiving a packet, the switch checks the packet against the ACL. If the ACL
permits the packet, the switch continues to process the packet. If the ACL rejects the packet, the switch
discards the packet.
When you apply an undefined ACL to an interface, the switch acts as if the ACL has not been applied to
the interface and permits all packets. Remember this behavior if you use undefined ACLs for network
security.

Displaying ACL Information

You can display the ACLs that are configured on the switch, and you can display the ACLs that have
been applied to physical and management interfaces. This section consists of these topics:
•
•

Displaying ACLs

You can display existing ACLs by using show commands.
Beginning in privileged EXEC mode, follow these steps to display access lists:
Command
Step 1 show access-lists [number | name]
Step 2
show ip access-list [number | name]
78-11380-10
Purpose
Return to privileged EXEC mode.
Display the access list configuration.
(Optional) Save your entries in the configuration file.
Displaying ACLs, page 29-21
Displaying Access Groups, page 29-22
Purpose
Show information about all IP and MAC address access lists or about a
specific access list (numbered or named).
Show information about all IP address access lists or about a specific IP
ACL (numbered or named).
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
Displaying ACL Information
29-21