动态主机配置协议

动态主机配置协议DHCP

作用：
在企业网络中通过使用动态主机配置协议DHCP,来为大量主机分配IP地址等网络参数可以减少管理员工作量，避免出错

DHCP角色：

• DHCP服务器
• DHCP客户端
• DHCP中继
  DHCP服务器
• windows server 2012
• centos7
• 路由器，三层交换
• 无线路由器

路由DHCP的三种模式：

• 全局模式
• 接口模式
• 中继代理模式
  1.DHCP工作原理
  discover 发现 寻找DHCP服务器 广播
  offer 回应 我是DHCP服务器 单播
  request 请求 请给我一个IP地址 广播
  ack 确认 给你IP 单播

2.租约更新
自动更新租约 50% 87.5%
手动更新租约 ipconfig /renew

3.租约释放
自动释放 客户机关机，网络中继，租约到期
手动释放 ipconfig /release

DHCP全局模式：永久

配置基于全局模式的DHCP服务器
[dhcp]dhcp enable //启用DHCP功能
[dhcp]ip pool xixi //创建地址池
[dhcp-ip-pool-xixi]network 192.168.1.0 mask 24 //指明网段和掩码
[dhcp-ip-pool-xixi]gateway-list 192.168.1.1 //指明网关
[dhcp-ip-pool-xixi]dns-list 202.106.0.20 //指明dns服务器地址
[dhcp-ip-pool-xixi]lease day 0 hour 1 minute 30 //指明租约
[dhcp-ip-pool-xixi]excluded-ip-address 192.168.1.200 192.168.1.254
//指明排除的地址范围

[dhcp]int g0/0/0
[dhcp-GigabitEthernet0/0/0]ip address 192.168.1.1 24
[dhcp-GigabitEthernet0/0/0]dhcp select global //启用DHCP全局模式

3.为接口启用DHCP功能
int g0/0/3
dhcp select global //接口下启用DHCP功能

DHCP接口模式：临时

配置基于接口模式的DHCP服务器
[r1]dhcp enable //启用DHCP功能
[r1]int g0/0/1
[r1-G0/0/1]ip address 192.168.2.1 24
[r1-G0/0/1]dhcp select interface //启用DHCP接口模式
此处隐含了DHCP网段和网关的设置，网段为接口IP所在网段，网关为接口IP，不可改变
[r1-G0/0/1]dhcp server dns-list 2.2.2.2
[r1-G0/0/1]dhcp server lease day 2
[r1-G0/0/1]dhcp server excluded-ip-address 192.168.2.200 192.168.2.254
如果重新配置了接口的IP地址，DHCP的所有配置就都不存在了

DHCP中继代理

配置中继代理服务器
在没有DHCP服务器的网段，需要配置DHCP中继代理服务器

[relay]dhcp enable
[relay]int g0/0/0 //进入跟客户端相连接口
[relay-G0/0/0]dhcp select relay //启用中继代理模式
[relay-G0/0/0]dhcp relay server-ip 192.168.2.1 //指明DHCP服务器地址

在三层交换机上配置DHCP服务

问题

配置两个地址池：192.168.1.0/24和192.168.2.0/24
配置两个VLAN：VLAN 10和VLAN 20
将四台主机分别加入VLAN
自动获取IP地址，确保全网互通

配置思路：

LSW1

1.创建VLAN

vlan batch 10 20
2.更改端口类型，并将端口加入VLAN
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
3.全局开启DHCP 服务
dhcp enable

4.创建地址池

ip pool 1
 gateway-list 192.168.1.254
 network 192.168.1.0 mask 255.255.255.0
 lease day 7 hour 0 minute 0
 dns-list 8.8.8.8
#
ip pool 2
 gateway-list 192.168.2.254
 network 192.168.2.0 mask 255.255.255.0
 lease day 7 hour 0 minute 0
 dns-list 8.8.8.8
5.配置网关地址，并在接口下启用DHCP功能
interface Vlanif10
 ip address 192.168.1.254 255.255.255.0
 dhcp select global
#
interface Vlanif20
 ip address 192.168.2.254 255.255.255.0
 dhcp select global

LSW2:
1.创建VLAN

vlan batch 10 20
2.更改接口类型，并将接口加入VLAN
interface Ethernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
interface Ethernet0/0/2
 port link-type access
 port default vlan 10
#
interface Ethernet0/0/3
 port link-type access
 port default vlan 10

LSW3:

 1.创建VLAN
vlan batch 10 20
2.更改接口类型，并将接口加入VLAN
interface Ethernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
interface Ethernet0/0/2
 port link-type access
 port default vlan 20
#
interface Ethernet0/0/3
 port link-type access
 port default vlan 20

测试：

pc1 ping pc3 pc4

PC>ipconfig

Link local IPv6 address...........: fe80::5689:98ff:fe29:1273
IPv6 address......................: :: / 128
IPv6 gateway......................: ::
IPv4 address......................: 192.168.1.253
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.1.254
Physical address..................: 54-89-98-29-12-73
DNS server........................: 8.8.8.8

```bash
PC>ping 192.168.2.250

Ping 192.168.2.250: 32 data bytes, Press Ctrl_C to break
From 192.168.2.250: bytes=32 seq=1 ttl=127 time=94 ms
From 192.168.2.250: bytes=32 seq=2 ttl=127 time=62 ms
From 192.168.2.250: bytes=32 seq=3 ttl=127 time=94 ms
From 192.168.2.250: bytes=32 seq=4 ttl=127 time=93 ms
From 192.168.2.250: bytes=32 seq=5 ttl=127 time=63 ms

--- 192.168.2.250 ping statistics ---
  5 packet(s) transmitted
  5 packet(s) received
  0.00% packet loss
  round-trip min/avg/max = 62/81/94 ms

PC>ping 192.168.2.253

Ping 192.168.2.253: 32 data bytes, Press Ctrl_C to break
From 192.168.2.253: bytes=32 seq=1 ttl=127 time=78 ms
From 192.168.2.253: bytes=32 seq=2 ttl=127 time=94 ms
From 192.168.2.253: bytes=32 seq=3 ttl=127 time=94 ms
From 192.168.2.253: bytes=32 seq=4 ttl=127 time=78 ms
From 192.168.2.253: bytes=32 seq=5 ttl=127 time=94 ms

--- 192.168.2.253 ping statistics ---
  5 packet(s) transmitted
  5 packet(s) received
  0.00% packet loss
  round-trip min/avg/max = 78/87/94 ms

pc2 ping pc3 pc4

PC>ipconfig

Link local IPv6 address...........: fe80::5689:98ff:feba:13e4
IPv6 address......................: :: / 128
IPv6 gateway......................: ::
IPv4 address......................: 192.168.1.250
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.1.254
Physical address..................: 54-89-98-BA-13-E4
DNS server........................: 8.8.8.8

PC>ping 192.168.2.253

Ping 192.168.2.253: 32 data bytes, Press Ctrl_C to break
From 192.168.2.253: bytes=32 seq=1 ttl=127 time=94 ms
From 192.168.2.253: bytes=32 seq=2 ttl=127 time=109 ms
From 192.168.2.253: bytes=32 seq=3 ttl=127 time=78 ms
From 192.168.2.253: bytes=32 seq=4 ttl=127 time=94 ms
From 192.168.2.253: bytes=32 seq=5 ttl=127 time=94 ms

--- 192.168.2.253 ping statistics ---
  5 packet(s) transmitted
  5 packet(s) received
  0.00% packet loss
  round-trip min/avg/max = 78/93/109 ms

PC>ping 192.168.2.250

Ping 192.168.2.250: 32 data bytes, Press Ctrl_C to break
From 192.168.2.250: bytes=32 seq=1 ttl=127 time=62 ms
From 192.168.2.250: bytes=32 seq=2 ttl=127 time=62 ms
From 192.168.2.250: bytes=32 seq=3 ttl=127 time=78 ms
From 192.168.2.250: bytes=32 seq=4 ttl=127 time=94 ms
From 192.168.2.250: bytes=32 seq=5 ttl=127 time=78 ms

--- 192.168.2.250 ping statistics ---
  5 packet(s) transmitted
  5 packet(s) received
  0.00% packet loss
  round-trip min/avg/max = 62/74/94 ms