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DHCP server can provide three types of IP address allocation policies according
to the different requirements:
■
Allocate addresses manually: Administrators configure special IP addresses for a
small number of particular hosts such as the service server WWW.
■
Allocate addresses automatically: Allocate permanent IP addresses for some
hosts connected to the network for the first time and the addresses will be
allocated to the hosts for a long period of time.
■
Allocate addresses dynamically: Allocate some addresses to client hosts by
means of “leasing”. In this case, the expiry date is limited and clients should
re-apply for new addresses upon the expiry. Most of clients are offered such
dynamic addresses.
Occasions in which DHCP server is applied
DHCP service is usually used to implement the allocation of IP addresses in the
following occasions:
■
Network scale is relatively large, manual configuration will consume an
enormous working volume and at the same time, it is difficult to centralize the
management of the overall network.
■
Hosts on the network are more than the IP addresses supported by this
network. That is, a fixed IP address cannot be allocated to each host. For
example, Internet accessing operators are in this situation. Numerous users
must dynamically obtain their own IP addresses through the DHCP service and
the number of simultaneous users is limited to a certain degree.
■
There are only a few hosts with their own fixed IP addresses on the network
(for example, various server hosts need fixed IP addresses) while most hosts
have no requirement for fixed IP addresses.
Fundamentals of DHCP
Server
Normally, a typical DHCP application network comprises of a DHCP server and
numerous client computers such as PCs and portable computers, as shown in the
following figure:
Figure 124
Typical networking application of DHCP server
To obtain a legal dynamic IP address (the processes of obtaining an auto-allocated
address and a manually allocated address are similar), a DHCP client should
interact different information with the server in different stages. Normally, there
are three types of modes:
LAN
DHCP clients
DHCP server
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 ...