Dhcp Relay Configuration Task List - Edge-Core ES4624-SFP Basic Management Manual

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 packets 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 DHCPREQUEST packet,
DHCP relay forwards the packet to the DHCP server after processing.
4. On receiving DHCPREQUEST, the DHCP server responds with a DHCPACK
packet via DHCP relay to the DHCP client.

14.3.1 DHCP Relay Configuration Task List

1. Enable DHCP relay.
2. Configure DHCP relay to forward DHCP broadcast packet.
3. 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
Global Mode
ip forward-protocol udp <port>
no ip forward-protocol
<port>
Port mode
ip helper-address <ipaddress>
no ip helper-address <ipaddress>
3. Disable DHCP relay from forwarding DHCP broadcast packet.
Command
Global Mode
ip dhcp relay information policy
drop
no ip dhcp relay information
policy drop
Explanation
The UDP port 67 is used for DHCP broadcast
udp
packet forwarding.
Set the destination IP address for DHCP relay
forwarding;
<ipaddress>" command cancels the setting.
Explanation
When layer 3 switches are used as DHCP
relays, this
forwarding policy to drop DHCP packets; the
"no ip dhcp relay information policy drop"
command allows DHCP packets forwarding.
420
the "no ip helper-address
command sets the relay