Download SMC SMC8150L2 UK network switch

4
DHCP Snooping Commands
Example
Console#show ip source-guard binding
MacAddress
IpAddress
Lease(sec) Type
VLAN Interface
----------------- --------------- ---------- -------------------- ---- ---11-22-33-44-55-66 192.168.0.99
0 Static
1 Eth 1/5
Console#
DHCP Snooping Commands
DHCP snooping allows a switch to protect a network from rogue DHCP servers or
other devices which send port-related information to a DHCP server. This
information can be useful in tracking an IP address back to a physical port. This
section describes commands used to configure DHCP snooping.
Table 4-78 DHCP Snooping Commands
Command
Function
Mode
ip dhcp snooping
Enables DHCP snooping globally
GC
Page
ip dhcp snooping vlan
Enables DHCP snooping on the specified VLAN
GC
4-233
ip dhcp snooping trust
Configures the specified interface as trusted
IC
4-234
ip dhcp snooping verify
mac-address
Verifies the client’s hardware address stored in the DHCP
GC
packet against the source MAC address in the Ethernet header
4-235
ip dhcp snooping
information option
Enables or disables DHCP Option 82 information relay
GC
4-235
ip dhcp snooping
information policy
Sets the information option policy for DHCP client packets that GC
include Option 82 information
4-236
show ip dhcp snooping
Shows the DHCP snooping configuration settings
PE
4-237
show ip dhcp snooping
binding
Shows the DHCP snooping binding table entries
PE
4-237
4-231
ip dhcp snooping
This command enables DHCP snooping globally. Use the no form to restore the
default setting.
Syntax
[no] ip dhcp snooping
Default Setting
Disabled
Command Mode
Global Configuration
Command Usage
• Network traffic may be disrupted when malicious DHCP messages are
received from an outside source. DHCP snooping is used to filter DHCP
messages received on an unsecure interface from outside the network or
4-231