Cisco 4500M Command Reference

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Catalyst4500 Series SwitchCiscoIOS Command Reference—Release 12.2(18)EW
78-16201-01
Chapter2Cisco IOS Commands for the Catalyst 4500 Series Switches
ip verify header vlan all
ip verify header vlan all
To enable IP header validation for Layer 2-switched IPv4 packets, use the ip verify header vlan all
command. To disable the IP header validation, use the no form of this command.
ip verify header vlan all
no ip verify header vlan all
Syntax Description This command has no default settings.
Defaults The IP header is validated for bridged and routed IPv4 packets.
Command Modes Configuration
Command History
Usage Guidelines This command does not apply to Layer 3-switched (routed) packets
The Catalyst 4500 series switch checks the validity of the following fields in the IPv4 header for all
switched IPv4 packets:
• Version must be 4.
• Header length must be greater than or equal to 20 bytes.
• Total length must be greater than or equal to four times the header length, and greater than the Layer
2 packet size minus the Layer 2 encapsulation size.
If an IPv4 packet fails the IP header validation, the packet is dropped. If you disable header validation,
packets with invalid IP headers are bridged but not routed even if routing was intended. IPv4 access lists
also are not applied to IP headers.
Examples This example shows how to disable IP header validation for Layer 2-switched IPv4 packets:
Switch# config t
Switch(config)# no ip verify header vlan all
Switch(config)# end
Switch#
Release Modification
12.1(20)EW Support for this command was introduced on the Catalyst 4500 series switch.

Cisco 4500M Specifications

General

Brand	Cisco
Model	4500M
Category	Network Router
Language	English