Accton Technology ES4710BD manual Dhcp Relay Configuration Task Sequence, Enable Dhcp relay

ES4710BD 10 Slots L2/L3/L4 Chassis Switch

Fig 14-2 DHCP relay

As shown in the above figure, the DHCP client and the DHCP server are in different networks, the DHCP client performs the four DHCP steps as usual yet DHCP relay is added to the process.

1.The client broadcasts a DHCPDISCOVER packet, and DHCP relay inserts its own IP address to the relay agent field in the DHCPDISCOVER packet on receiving the packet, and forwards the packet to the specified DHCP server (for DHCP frame format, please refer to RFC2131).

2.On the receiving the DHCPDISCOVER packet forwarded by DHCP relay, the DHCP server sends the DHCPOFFER packet via DHCP relay to the DHCP client.

3.DHCP client chooses a DHCP server and broadcasts a DHCPREPLY packet, DHCP relay forwards the packet to the DHCP server after processing.

4.On receiving DHCPREPLY, the DHCP server responds with a DHCPACK packet via DHCP relay to the DHCP client.

DHCP relay can not only send DHCP broadcasting packets to the specified DHCP servers, but can also send other specified UDP broadcast packet to specified servers.

14.3.1DHCP Relay Configuration Task Sequence

1.Enable DHCP relay.

2.Configure DHCP relay to forward DHCP broadcast packet.

3.Configure DHCP relay to forward other UDP broadcast packet.

4.Disable DHCP relay from forwarding DHCP broadcast packet.

1.Enable DHCP relay.

DHCP server and DHCP relay is enabled as the DHCP service is enabled..

2.Configure DHCP relay to forward DHCP broadcast packet.

	Command	Explanation
	Global Mode
	ip forward-protocol udp <port>	The UDP port used for DHCP broadcast packet
	no ip forward-protocol udp <port>	forwarding.
	Interface Mode
	ip helper-address <ipaddress>	Sets the destination		IP address		for DHCP relay
		forwarding;	the	“no	ip	helper-address
	no ip helper-address <ipaddress>
		<ipaddress>” command cancels the setting.
3. Configure DHCP relay to forward other UDP broadcast packet.
	Command	Explanation
	Global Mode
	ip forward-protocol udp <port>	Specifies the DHCP relay forwarding protocol by
		setting UDP port; the “no ip forward-protocol
	no ip forward-protocol udp <port>
		udp <port>” command cancels the setting.
	ip helper-address <ipaddress>	Sets the destination		IP address		for DHCP relay
		forwarding;	the	“no	ip	helper-address
	no ip helper-address <ipaddress>
		<ipaddress>” command cancels the setting.
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