Siemens S223 - Manual (Page 251)

User Manual UMN:CLI
SURPASS hiD 6615 S223/S323 R1.5
A50010-Y3-C150-2-7619 251
Before configuring DHCP server or relay, you need to use the service dhcp command
first to activate the DHCP function in the system.
8.8.4.1 Packet Forwarding Address
A DHCP client sends DHCP_DISCOVER message to a DHCP server. DHCP_DISCOVER
message is broadcasted within the network to which it is attached. If the client is on a
network that does not have any DHCP server, the broadcast is not forwarded because
the switch is configured to not forward broadcast traffic. To solve this problem, you can
configure the interface that is receiving the broadcasts to forward certain classes of
broadcast to a helper address.
To specify a packet forwarding address, use the following command.
Command Mode Description
ip dhcp helper-address A.B.C.D
Specifies a packet forwarding address. More than one
address is possible.
A.B.C.D: DHCP server address
no ip dhcp helper-address
{A.B.C.D | all}
Interface
Deletes a specified packet forwarding address.
If a packet forwarding address is specified on an interface, the hiD 6615 S223/S323 will
enable a DHCP relay agent.
You can also specify an organizationally unique identifier (OUI) when configuring a packet
forwarding address. The OUI is a 24-bit number assigned to a company or organization
for use in various network hardware products which is a first 24 bits of a MAC address. If
an OUI is specified, a DHCP relay agent will forward DHCP_DISCOVER message to a
specific DHCP server according to a specified OUI.
To specify a packet forwarding address with an OUI, use the following command.
Command Mode Description
ip dhcp oui XX:XX:XX helper-
address A.B.C.D
Specifies a packet forwarding address with an OUI.
More than one address is possible.
XX:XX:XX: OUI (first 24 bits of a MAC address in the
form of hexadecimal)
A.B.C.D: DHCP server address
no ip dhcp oui XX:XX:XX
[helper-address A.B.C.D]
Interface
Deletes a specified packet forwarding address.
8.8.4.2 Smart Relay Agent Forwarding
Normally, a DHCP relay agent forwards DHCP_DISCOVER message to a DHCP server
only with a primary IP address on an interface, even if there is more than one IP address
on the interface.
If the smart relay agent forwarding is enabled, a DHCP relay agent will retry sending
DHCP_DISCOVER message with a secondary IP address, in case of no response from
the DHCP server.
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