DHCP及相關企業拓撲
Dynamic host configuration protocol 動態主機配置協議
一、為什麽會有dhcp
在現在的企業網絡中，有大量的主機或設備需要獲取ip地址，如果使用手工配置，工作量大、容易出錯且不好管理；如果采用用戶擅自更改，還有可能會造成ip地址沖突等問題。
因此，使用DHCP來分配ip地址等網絡參數，可以減少管理員的工作量，避免出錯
二、作用：
用於實現企業用戶ip地址的動態分配和集中管理，避免繁瑣的手工配置，快速適應網絡的變化
三、角色：
DHCP客戶端：通過dhcp協議請求獲取ip地址的設備，例如pc,手機，ip電話
DHCP服務器：負責為DHCP客戶端分配網絡參數的設備
四、工作過程：
（1）首次接入
（2）地址重用
（3）更新租期
前提：
PC機開啟DHCP
方法一：
基於全局的dhcp（路由器）：
1.開啟dhcp
[Huawei]dhcp enable
2.建立地址池abc
[Huawei]ip pool abc
3.設置網段，網關，dns地址
[Huawei-ip-pool-abc]network 192.168.2.0 mask 255.255.255.0
[Huawei-ip-pool-abc]gateway-list 192.168.2.254
[Huawei-ip-pool-abc]dns-list 1.1.1.1
4.進入接口配置ip
[Huawei]interface gi0/0/0
[Huawei-GigabitEthernet0/0/0]ip add 192.168.2.254 24
5.dhcp選擇全局模式
[Huawei-GigabitEthernet0/0/0]dhcp select global
方法二：基於接口的dhcp：
PC機開啟DHCP
路由器：
1.開啟dhcp [Huawei]dhcp enable
2.進入接口配置ip
[Huawei]interface gi0/0/0
[Huawei-GigabitEthernet0/0/0]ip add 192.168.1.254 24
3.讓dhcp選擇接口模式
4.設置dns地址
[Huawei-GigabitEthernet0/0/0]dhcp server dns-list 1.2.3.0
五：實驗
實驗1：交換機充當server服務器
PC5：VLAN10
PC6：VLAN 20
[Huawei]dhcp enable
[Huawei]vlan batch 10 20
[Huawei]interface gi0/0/1
[Huawei-GigabitEthernet0/0/1]port link-type access
[Huawei-GigabitEthernet0/0/1]port default vlan 10
[Huawei-GigabitEthernet0/0/1]q
[Huawei]ip pool abc
[Huawei-ip-pool-abc]network 192.168.1.0 mask 255.255.255.0
[Huawei-ip-pool-abc]gateway-list 192.168.1.254
[Huawei-ip-pool-abc]dns-list 1.1.1.1
[Huawei-ip-pool-abc]q
[Huawei]interface vlanif 10
[Huawei-Vlanif10]ip add 192.168.1.254 24
[Huawei-Vlanif10]dhcp select global
PC6再設一個地址池
[Huawei]ip pool bcd
[Huawei-ip-pool-bcd]network 192.168.2.0 mask 255.255.255.0
[Huawei-ip-pool-bcd]gateway-list 192.168.2.254
[Huawei-ip-pool-bcd]dns-list 1.1.1.1
[Huawei-ip-pool-bcd]q
[Huawei]interface gi0/0/2
[Huawei-GigabitEthernet0/0/2]port link-type access
[Huawei-GigabitEthernet0/0/2]port default vlan 20
[Huawei-GigabitEthernet0/0/2]q
[Huawei]interface vlanif 20
[Huawei-Vlanif20]ip add 192.168.2.254 24
[Huawei-Vlanif20]dhcp select global
將PC5 PC6設置好自動獲取dhcp
驗證：
實驗二：路由充當server服務器，通過一個路由器來配置ip
[AR14]interface gi0/0/0
[AR14-GigabitEthernet0/0/0]ip add 192.168.2.2 24
[AR14-GigabitEthernet0/0/0]q
[AR14]dhcp enable
[AR14]ip pool abc
[AR14-ip-pool-abc]network 192.168.1.0 mask 255.255.255.0
[AR14-ip-pool-abc]gateway-list 192.168.1.254
[AR14-ip-pool-abc]dns-list 1.1.1.1
[AR14-ip-pool-abc]q
[AR14]interface gi0/0/0
[AR14-GigabitEthernet0/0/0]dhcp select global
[AR14-GigabitEthernet0/0/0]q
[AR14]ip route-static 192.168.1.0 24 192.168.2.1
[AR15]interface gi0/0/1
[AR15-GigabitEthernet0/0/1]ip add 192.168.2.1 24
[AR15-GigabitEthernet0/0/1]q
[AR15]interface gi 0/0/0
[AR15-GigabitEthernet0/0/0]ip add 192.168.1.254 24
[AR15-GigabitEthernet0/0/0]q
[AR15]dhcp enable
[AR15]inter gi0/0/0
[AR15-GigabitEthernet0/0/0]dhcp select relay
[AR15-GigabitEthernet0/0/0]dhcp relay server-ip 192.168.2.2
驗證：
實驗三：路由器充當server服務器，中間通過交換機分配
AR17:
[Huawei]dhcp enable
[Huawei]interface gi0/0/0
[Huawei-GigabitEthernet0/0/0]ip add 192.168.20.2 24
[Huawei-GigabitEthernet0/0/0]q
[Huawei]ip pool v17
Info: It‘s successful to create an IP address pool.
[Huawei-ip-pool-v17]network 192.168.17.0 mask 255.255.255.0
[Huawei-ip-pool-v17]gateway-list 192.168.17.254
[Huawei-ip-pool-v17]dns-list 1.1.1.1
[Huawei-ip-pool-v17]q
[Huawei]interface gi 0/0/0
[Huawei-GigabitEthernet0/0/0]dhcp select global
[Huawei-GigabitEthernet0/0/0]q
[Huawei]ip route-static 0.0.0.0 0.0.0.0 192.168.20.1
LW4:
[Huawei]dhcp enable
[Huawei]vlan batch 17 to 20
[Huawei]interface gi0/0/1
[Huawei-GigabitEthernet0/0/1]port link-type access
[Huawei-GigabitEthernet0/0/1]port default vlan 17
[Huawei-GigabitEthernet0/0/1]q
[Huawei]interface vlanif 17
[Huawei-Vlanif17]ip add 192.168.17.254 24
[Huawei-Vlanif17]dhcp select relay
[Huawei-Vlanif17]dhcp relay server-ip 192.168.20.2
[Huawei-Vlanif17]q
[Huawei]interface gi 0/0/4
[Huawei-GigabitEthernet0/0/4]port link-type access
[Huawei-GigabitEthernet0/0/4]port default vlan 20
[Huawei-GigabitEthernet0/0/4]q
[Huawei]interface vlanif 20
[Huawei-Vlanif20]ip add 192.168.20.1 24
vlan18 19步驟同上，此實驗要設置四個vlan，三個地址池，每個地址池名字都不同，配置好後三臺pc可連通
DHCP及相關企業拓撲