Cisco Systems 3750E manual Enabling IP Source Guard, 22-18

Chapter 22 Configuring DHCP Features and IP Source Guard

Configuring IP Source Guard

•When configuring IP source guard on interfaces on which a private VLAN is configured, port security is not supported.

•IP source guard is not supported on EtherChannels.

•You can enable this feature when IEEE 802.1x port-based authentication is enabled.

•If the number of hardware entries exceeds the maximum available, the CPU usage increases.

Enabling IP Source Guard

Beginning in privileged EXEC mode, follow these steps to enable and configure IP source guard on an interface.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	interface interface-id	Specify the interface to be configured, and enter interface configuration
		mode.
Step 3
	ip verify source	Enable IP source guard with source IP address filtering.
	or
	ip verify source port-security	Enable IP source guard with source IP and MAC address filtering.
		Note When you enable both IP Source Guard and Port Security by
		using the ip verify source port-securityinterface configuration
		command, there are two caveats:
		• The DHCP server must support option 82, or the client is not
		assigned an IP address.
		• The MAC address in the DHCP packet is not learned as a secure
		address. The MAC address of the DHCP client is learned as a
		secure address only when the switch receives non-DHCP data
		traffic.
Step 4
	exit	Return to global configuration mode.
Step 5
	ip source binding mac-addressvlan	Add a static IP source binding.
	vlan-id ip-address inteface interface-id	Enter this command for each static binding.
Step 6
	end	Return to privileged EXEC mode.
Step 7
	show ip verify source [interface	Display the IP source guard configuration for all interfaces or for a
	interface-id]	specific interface.
Step 8
	show ip source binding [ip-address]	Display the IP source bindings on the switch, on a specific VLAN, or on
	[mac-address][dhcp-snooping static]	a specific interface.
	[inteface interface-id] [vlan vlan-id]
Step 9
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To disable IP source guard with source IP address filtering, use the no ip verify source interface configuration command.

To delete a static IP source binding entry, use the no ip source global configuration command.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
22-18	OL-9775-02