Cisco Catalyst 4500 Series - Ip Verify Header Vlan All

2-351
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
OL-27596 -01
Chapter 2 Cisco 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 Global configuration mode
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:
• The version must be 4.
• The header length must be greater than or equal to 20 bytes.
• The 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 the header
validation, the packets with the invalid IP headers are bridged but are not routed even if routing was
intended. The IPv4 access lists also are not applied to the IP headers.
Examples This example shows how to disable the IP header validation for the Layer 2-switched IPv4 packets:
Switch# config terminal
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.