ICP DAS USA MSM-6226 user manual Dhcp Relay State

3-3. DHCP Relay

The Dynamic Host Configuration Protocol (DHCP) is a service that runs at the application layer of the TCP/IP protocol stack to dynamically assign IP addresses to DHCP clients. DHCP clients request IP addresses, and obtain leases for IP addresses from the DHCP server.

The DHCP Relay Agent makes it possible for DHCP broadcast messages to be sent over routers that do not support forwarding of these types of messages. The DHCP Relay Agent is therefore the routing protocol that enables DHCP clients to obtain IP addresses from a DHCP server on a remote subnet, or which is not located on the local subnet. If you have no configured DHCP Relay Agent, your clients would only be able to obtain IP addresses from the DHCP server which is on the same subnet.

If you are using the switches to insert DHCP Option 82 information and you are also using as DHCP relay-agents (via ‘ip helper-address’), you’ll notice right away that your Option 82 enabled DHCP requests are not being forwarded by your switches.

Function name:

Config

Function description:

The switch to enable clients to obtain IP addresses from a DHCP server on a remote subnet, you have to configure the DHCP Relay Agent on the subnet that contains the remote clients, so that it can relay DHCP broadcast messages to your DHCP server.

Fig. 3-13-1

Parameters description:

DHCP Relay State:

46	Publication date:March., 2011
	Revision A1