Dhcp Relayagent - Supermicro SSE-G24-TG4 Configuration Manual

SMIS(config-if)# end
SMIS# show ip interface
Gi0/22 is up, line protocol is up
Internet Address is 192.168.1.6/24
Broadcast address is 192.168.1.255
IP address allocation method is dynamic
IP address allocation protocol is dhcp
mgmt is up, line protocol is down
Internet address is 192.168.100.102/24
Broadcast address is 192.168.100.255
Gateway is 0.0.0.0

1.6.8 DHCP RelayAgent

In small networks with only one IP subnet, DHCP clients can communicate directly with DHCP servers. In
large networks, DHCP servers provide IP addresses for multiple subnets. In such cases, a DHCP client
that has not yet obtained an IP address from the DHCP server cannot communicate with the DHCP
server using IP routing. A DHCP relay agent forwards DHCP packets between clients and servers when
they are not on the same physical subnet.
DHCP Discover
DHCP Offer
DHCP Request
DHCP Ack
DHCP
Client
Figure IP-4: DHCP Relay Agent
The relay agent receives the broadcast from the DHCP client and unicasts it to one or more DHCP
servers. The relay agent stores its own IP address in the GIADDR field of the DHCP packet. The DHCP
server uses the GIADDR to determine the subnet on which the relay agent received the broadcast and
allocates an IP address on that subnet. When the DHCP server replies to the client, it unicasts the reply
to the GIADDR address. The relay agent then retransmits the response on the local network.
DHCP Relay Agent
(Optional)
Supermicro L2/L3 Switches Configuration Guide
DHCP Discover
DHCP Offer
DHCP Request
DHCP Ack
DHCP
Server
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