Chapter 9
| General Security Measures
DHCPv4 Snooping
– 346 –
Command Mode
Global Configuration
Command Usage
If MAC address verification is enabled, and the source MAC address in the Ethernet
header of the packet is not same as the client’s hardware address in the DHCP
packet, the packet is dropped.
Example
This example enables MAC address verification.
Console(config)#ip dhcp snooping verify mac-address
Console(config)#
Related Commands
ip dhcp snooping (339)
ip dhcp snooping vlan (346)
ip dhcp snooping trust (348)
ip dhcp snooping vlan This command enables DHCP snooping on the specified VLAN. Use the no form to
restore the default setting.
Syntax
[no] ip dhcp snooping vlan vlan-id
vlan-id - ID of a configured VLAN (Range: 1-4094)
Default Setting
Disabled
Command Mode
Global Configuration
Command Usage
â—† When DHCP snooping is enabled globally using the ip dhcp snooping
command, and enabled on a VLAN with this command, DHCP packet filtering
will be performed on any untrusted ports within the VLAN as specified by the ip
dhcp snooping trust command.
â—† When the DHCP snooping is globally disabled, DHCP snooping can still be
configured for specific VLANs, but the changes will not take effect until DHCP
snooping is globally re-enabled.
â—† When DHCP snooping is globally enabled, and then disabled on a VLAN, all
dynamic bindings learned for this VLAN are removed from the binding table.