mac

Commands for DHCP
314
Parameter: None.
Default: Disable.
Command Mode: Global mode
Usage Guide: Suppress the forwarding about DHCP broadcast packets, namely, drop or
copy DHCP broadcast packets to CPU.
Example: Enable DHCP broadcast suppress function.
Switch(config)#ip dhcp broadcast suppress
26.2.2 ip dhcp relay share-vlan <vlanid> sub-vlan
<vlanlist>
Command: ip dhcp relay share-vlan <vlanid> sub-vlan <vlanlist>
no ip dhcp relay share-vlan
Function: Specify sub-vlan of a share-vlan, the no command cancels sub-vlan.
Parameter: <vlanid> is VLAN ID of share-vlan, <vlanlist> is sub-vlan list.
Default: None.
Command Mode: Global mode.
Usage Guide: share-vlan may include many sub-vlan, but a sub-vlan only corresponds
to a share-vlan. When layer 2 device of DHCP Relay receive DHCP Request, firstly
judge whether VLAN with layer 3 interface for receiving package. If there is layer 3
interface in package, use the interface to process DHCP Relay, or else use layer 3
interface of share-vlan to process DHCP Relay when the vlan is sub-vlan of share-vlan.
26.2.3 ip forward-protocol udp bootps
Command: ip forward-protocol udp bootps
no ip forward-protocol udp bootps
Function: Sets DHCP relay to forward UPD broadcast packets on the port; the “no ip
forward-protocol udp bootps”command cancels the service.
Parameter: bootps forwarding UDP port as 67 DHCP broadcast packets.
Default: Not forward UPD broadcast packets by default.
Command mode: Global Mode
Usage Guide: The forwarding destination address is set in the “ip helper-address”
command and described later.
Example: Setting DHCP packets to be forwarded to 192.168.1.5.
Switch(config)#ip forward-protocol udp boots
Switch(config)#interface vlan 1
Switch(Config-if-Vlan1)#ip helper-address 192.168.1.5