Configure DHCP Relay
345
Figure 127
Schematic diagram of DHCP relay
The above figure is the schematic diagram of DHCP relay. Its working principle is as
follows:
After starting DHCP client, a configuration request message is broadcast and the
DHCP relay router will send the message to the designated DHCP server on the
other network after processing it properly. According to the information provided
by the client, the server sends configuration information to the client via DHCP
relay and completes the dynamic configuration of host.
DHCP relay actually realizes transparent transmission of broadcast messages, i.e.
transmitting broadcast messages of DHCP clients to DHCP servers on other
network segments. Besides, the user can also configure transparent transmission
for broadcast messages of designated protocols as required, to enable specific
protocol broadcast messages of this network segment to arrive at other network
segments. Similarly, the destinations are specified by IP auxiliary addresses. For
example, transmit TFTP and DNS protocol messages transparently to
corresponding servers.
To implement the DHCP relay, users have to configure IP auxiliary addresses to
specify the DHCP server addresses.
Configure DHCP Relay
DHCP configuration includes:
■
Configure interface relay address
■
Configure transparent transmission forwarding protocol.
1
Configure interface relay address
To implement DHCP relay function, you need to configure IP relay address to
specify DHCP server address. For DHCP relay, IP relay address specifies DHCP
server. After configuration the broadcast messages received by this interface will
be sent to the relay address. The interface configured with IP helper address
should support broadcast mode. An interface can be configured with up to 20
relay addresses.
Perform the following task in Ethernet interface view.
Table 380
Configure interface relay address
By default, an interface has no IP address.
2
Configure transparent transmission forwarding protocol
Network
DHCP client
DHCP client
DHCP trunk router
DHCP server
Operation
Command
Configure interface relay address
ip relay-address
ip-address
Delete interface relay address
undo ip relay-address [
ip-address
]
Summary of Contents for 3036
Page 1: ...http www 3com com 3Com Router Configuration Guide Published March 2004 Part No 10014299 ...
Page 4: ...VPN 615 RELIABILITY 665 QOS 681 DIAL UP 721 ...
Page 6: ...2 ABOUT THIS GUIDE ...
Page 7: ...I GETTING STARTED Chapter 1 3Com Router Introduction Chapter 2 3Com Router User Interface ...
Page 8: ...4 ...
Page 16: ...12 CHAPTER 1 3COM ROUTER INTRODUCTION ...
Page 34: ...30 ...
Page 60: ...56 CHAPTER 3 SYSTEM MANAGEMENT ...
Page 98: ...94 CHAPTER 6 DISPLAY AND DEBUGGING TOOLS ...
Page 110: ...106 ...
Page 114: ...110 CHAPTER 8 INTERFACE CONFIGURATION OVERVIEW ...
Page 158: ...154 CHAPTER 10 CONFIGURING WAN INTERFACE ...
Page 168: ...164 ...
Page 188: ...184 CHAPTER 13 CONFIGURING PPPOE CLIENT ...
Page 192: ...188 CHAPTER 14 CONFIGURING SLIP Router ip route static 0 0 0 0 0 0 0 0 10 110 0 1 ...
Page 248: ...244 CHAPTER 16 CONFIGURING LAPB AND X 25 ...
Page 320: ...316 ...
Page 330: ...326 CHAPTER 20 CONFIGURING IP ADDRESS ...
Page 362: ...358 CHAPTER 21 CONFIGURING IP APPLICATION ...
Page 374: ...370 CHAPTER 23 CONFIGURING IP COUNT ...
Page 406: ...402 CHAPTER 25 CONFIGURING DLSW ...
Page 408: ...404 ...
Page 452: ...448 CHAPTER 29 CONFIGURING OSPF ...
Page 482: ...478 CHAPTER 30 CONFIGURING BGP ...
Page 494: ...490 CHAPTER 31 CONFIGURING IP ROUTING POLICY ...
Page 502: ...498 ...
Page 508: ...504 CHAPTER 33 IP MULTICAST ...
Page 514: ...510 CHAPTER 34 CONFIGURING IGMP ...
Page 526: ...522 CHAPTER 36 CONFIGURING PIM SM ...
Page 528: ...524 ...
Page 532: ...528 CHAPTER 37 CONFIGURING TERMINAL ACCESS SECURITY ...
Page 550: ...546 CHAPTER 38 CONFIGURING AAA AND RADIUS PROTOCOL ...
Page 590: ...586 CHAPTER 40 CONFIGURING IPSEC ...
Page 599: ...IX VPN Chapter 42 Configuring VPN Chapter 43 Configuring L2TP Chapter 44 Configuring GRE ...
Page 600: ...596 ...
Page 638: ...634 CHAPTER 43 CONFIGURING L2TP ...
Page 649: ...X RELIABILITY Chapter 45 Configuring a Standby Center Chapter 46 Configuring VRRP ...
Page 650: ...646 ...
Page 666: ...662 ...
Page 670: ...666 CHAPTER 47 QOS OVERVIEW ...
Page 700: ...696 CHAPTER 49 CONGESTION MANAGEMENT ...
Page 706: ...702 CHAPTER 50 CONGESTION AVOIDANCE ...
Page 707: ...XII DIAL UP Chapter 51 Configuring DCC Chapter 52 Configuring Modem ...
Page 708: ...704 ...
Page 762: ...758 CHAPTER 52 CONFIGURING MODEM ...