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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 19 Configuring Network Security with ACLs
Configuring Router ACLs
Beginning in privileged EXEC mode, follow these steps to restrict incoming and outgoing connections
between a virtual terminal line and the addresses in an ACL:
To remove access restrictions on a terminal line, use the no access-class access-list-number {in | out}
line configuration command.
Beginning in privileged EXEC mode, follow these steps to control access to a Layer 3 interface:
To remove the specified access group, use the no ip access-group {access-list-number | name} {in | out}
interface configuration command.
This example shows how to apply access list 2 on Gigabit Ethernet interface 0/3 to filter packets entering
the interface:
Switch(config)# interface gigabitethernet0/3
Router(config-if)# ip access-group 2 in
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
line [console | vty] line-number
Identify a specific line for configuration, and enter in-line configuration
mode.
•
console—Enter to specify the console terminal line. The console port
is DCE.
•
vty—Enter to specify a virtual terminal for remote console access.
The line-number is the first line number in a contiguous group that you want
to configure when the line type is specified. The range is from 0 to 16.
Step 3
access-class access-list-number
{in | out}
Restrict incoming and outgoing connections between a particular virtual
terminal line (into a device) and the addresses in an access list.
Step 4
end
Return to privileged EXEC mode.
Step 5
show running-config
Display the access list configuration.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Identify a specific interface for configuration, and enter interface
configuration mode.
The interface must be a Layer 3 interface, either a routed port or an SVI
VLAN ID.
Step 3
ip access-group {access-list-number |
name} {in | out}
Control access to the specified interface.
Step 4
end
Return to privileged EXEC mode.
Step 5
show running-config
Display the access list configuration.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.