理论+实验——（Linux网络）DHCP原理与配 置

一、了解DNCP服务

使用DHCP的好处：

• 减少管理员的工作量
• 避免输入错误的可能
• 避免IP地址冲突
• 当更改IP地址段时，不需要重新分配每个用户的IP地址
• 提高了IP地址的利用率
• 方便客户端的配置

DHCP的分配方式：

• 自动分配：分配到一个IP地址后永久使用
• 手动分配：由DHCP服务器管理员专门指定IP地址
• 动态分配：使用完后释放该IP，供其他客户机使用

二、DHCP的租约过程

三、DHCP服务器的配置

四、DHCP客户端的配置

五、DHCP中继原理与配置

DHCP配置文件

vi /etc/dhcp/dhcp.conf

ddns-update-style none;
subnet 192.168.100.0 netmask 255.255.255.0 {
range 192.168.100.100 192.168.100.200;
option routers 192.168.100.1;
option subnet-mask 255.255.255.0;
option domain-name "www.bdqn.com";
option domain-name-servers 114.114.114.114 8.8.8.8;
option broadcast-address 192.168.100.255;
default-lease-time 21600;
max-lease-time 43200;
host prtsvr {
hardware ethernet 00:0C:29:BC:CF:2F;   ###第二台客户机的MAC地址
fixed-address 192.168.100.66;
  }
}

#ddns-update-style none;
subnet 192.168.10.0 netmask 255.255.255.0 {
range 192.168.10.100 192.168.10.200;
option routers 192.168.10.1;
option subnet-mask 255.255.255.0;
option domain-name "www.bdqn1.com";
#option domain-name-servers 114.114.114.114 8.8.8.8;
#option broadcast-address 192.168.100.255;
default-lease-time 21600;
max-lease-time 43200;
#host prtsvr {
#hardware ethernet 00:0C:29:BC:CF:2F;   ###第二台客户机的MAC地址
#fixed-address 192.168.100.66;
#  }
}

#ddns-update-style none;
subnet 192.168.20.0 netmask 255.255.255.0 {
range 192.168.20.100 192.168.20.200;
option routers 192.168.20.1;
option subnet-mask 255.255.255.0;
option domain-name "www.bdqn2.com";
#option domain-name-servers 114.114.114.114 8.8.8.8;
#option broadcast-address 192.168.100.255;
default-lease-time 21600;
max-lease-time 43200;
#host prtsvr {
#hardware ethernet 00:0C:29:BC:CF:2F;   ###第二台客户机的MAC地址
#fixed-address 192.168.100.66;
#  }
}

拓扑图配置

SW2

<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname SW2
[SW2]v b 10 20 30
Info: This operation may take a few seconds. Please wait for a moment...done.
[SW2]int e0/0/1
[SW2-Ethernet0/0/1]p l a
[SW2-Ethernet0/0/1]p d v 10
[SW2-Ethernet0/0/1]un sh
Info: Interface Ethernet0/0/1 is not shutdown.
[SW2-Ethernet0/0/1]int e0/0/2
[SW2-Ethernet0/0/2]p l a
[SW2-Ethernet0/0/2]p d v 20
[SW2-Ethernet0/0/2]un sh
Info: Interface Ethernet0/0/2 is not shutdown.
[SW2-Ethernet0/0/2]int e0/0/3
[SW2-Ethernet0/0/3]p l a
[SW2-Ethernet0/0/3]p d v 30
[SW2-Ethernet0/0/3]un sh
Info: Interface Ethernet0/0/3 is not shutdown.
[SW2-Ethernet0/0/3]int g0/0/1
[SW2-GigabitEthernet0/0/1]p l a
[SW2-GigabitEthernet0/0/1]p l t
[SW2-GigabitEthernet0/0/1]p t a v a
[SW2-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[SW2-GigabitEthernet0/0/1]q
[SW2]

RSW1

<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname RWS1
[RWS1]dhcp enable 
Info: The operation may take a few seconds. Please wait for a moment.done.
[RWS1]v b 10 20 30
Info: This operation may take a few seconds. Please wait for a moment...done.
[RWS1]int g0/0/1
[RWS1-GigabitEthernet0/0/1]p l t
[RWS1-GigabitEthernet0/0/1]p t a v a
[RWS1-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[RWS1-GigabitEthernet0/0/1]q	
[RWS1]int Vlanif 10
[RWS1-Vlanif10]ip add 192.168.10.1 24
[RWS1-Vlanif10]dhcp select relay 	
[RWS1-Vlanif10]dhcp relay server-ip 192.168.100.10
[RWS1-Vlanif10]q	
[RWS1]int Vlanif 20
[RWS1-Vlanif20]ip add 192.168.20.1 24
[RWS1-Vlanif20]dhcp select relay 
[RWS1-Vlanif20]dhcp relay server-ip 192.168.100.10
[RWS1-Vlanif20]q	
[RWS1]int Vlanif 30
[RWS1-Vlanif30]ip add 192.168.100.1 24
[RWS1-Vlanif30]q
[RWS1]ping 192.168.100.10
  PING 192.168.100.10: 56  data bytes, press CTRL_C to break
    Reply from 192.168.100.10: bytes=56 Sequence=1 ttl=64 time=50 ms
    Reply from 192.168.100.10: bytes=56 Sequence=2 ttl=64 time=50 ms
    Reply from 192.168.100.10: bytes=56 Sequence=3 ttl=64 time=50 ms
    Reply from 192.168.100.10: bytes=56 Sequence=4 ttl=64 time=60 ms

  --- 192.168.100.10 ping statistics ---
    4 packet(s) transmitted
    4 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 50/52/60 ms

[RWS1]ping 192.168.100.10
  PING 192.168.100.10: 56  data bytes, press CTRL_C to break
    Reply from 192.168.100.10: bytes=56 Sequence=1 ttl=64 time=110 ms
    Reply from 192.168.100.10: bytes=56 Sequence=2 ttl=64 time=70 ms
    Reply from 192.168.100.10: bytes=56 Sequence=3 ttl=64 time=60 ms
    Reply from 192.168.100.10: bytes=56 Sequence=4 ttl=64 time=50 ms
    Reply from 192.168.100.10: bytes=56 Sequence=5 ttl=64 time=50 ms

  --- 192.168.100.10 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 50/68/110 ms