DHCP工作流程（一般情况下）
例二（无忧/22）
下图为DHCP客户机获取IP地址等配置信息时，使用Wareshark软件捕获报文中编号为2〜5的4条报文，图中对编号为3的报文进行了解析。分析图中的信息并补全图中①〜⑤处的信息
[1]192.168.1.36
[2]255.255.255.255
[3]offer
[]
[]
pconfig/all用于获取参数的信息
DHCP工作流程（续约：执行ipconfig/renew）
例一
某公司网络DHCP服务器地址为192.168.0.2，可分配IP地址为192.168.0.6-192.168.0.254，缺省网关的地址为192.168.0.1，DNS服务器地址为192.168.0.2。网络中某客户机从服务器获取IP地址后，在客户机上执行ping命令的过程中，连续捕获的4条报文及对第4条报文的部分解析如下图所示。请补全图中空白处的信息。
| 编号 | 源IP地址 | 目的IP地址 | 报文摘要 |
| 1 | 192.168.0.10 | 192.168.0.1 | Ping:Request |
| 2 | [1] | [2] | Ping:Reply |
| 3 | 192.168.0.10 | [3] |
DHCP:Request, Type: Request
|
| 4 | [4] | 192.168.0.10 |
DHCP:Reply, Type:Ack
|
|
DHCP:----- DHCP Header -----
DHCP: Boot record type = 2 (Reply)
DHCP: Hardware address type = 1 (10M Ethernet)
DHCP: Hardware address length = 6 bytes
DHCP: Client self-assigned address =[192.168.0.10]
DHCP: Client address = [192.168.0.10]
DHCP: Next Server to use in bootstrap = [0.0.0.0]
DHCP: Relay Agent = [0.0.0.0]
DHCP: Client hardware address = 001122334455
DHCP: VendorInformation tag = 63825363
DHCP: MessageType = 5
DHCP: Address renewel interval = 345600 (seconds)
DHCP: Address rebinding interval = 604800 (seconds)
DHCP: Request
IP Address lease time = 691200 (seconds)
DHCP: Subnet mask = 255.255.255.0
DHCP: Gateway address = [ [5]]
DHCP: Domain Name Server address = [192.168.0.2]
|
[1]192.168.0.1
[2]192.168.0.10
[3]192.168.0.2
[4]192.168.0.2
[5]192.168.0.1
DHCP（释放后重获地址ipconfig/relesse和ipconfig/renew）
例一
（无忧/23） 下图是在DHCP客户机上依次执行命令ipconfig /release和ipconfig /renew过程中，使用Wareshark软件捕获报文中的2条报文:图中对第2条报文进行了解析。
1.分析图中的信息并补全图中①〜⑤处的信息
[1][2]
我们可以观察到，这两幅图片“DHCP Discover”是一样的，【1】空指的是发送报文的ip，【2】空指的是接收报文的地址，正好对应【1】0.0.0.0 【2】255.255.255.255
[3]
[4]
Client MAC adress 指的是客户机的物理地址
通过这个图我们可以看出来客户机的ip地址192.168.1.1
[5]
例二
如下图所示，在某DHCP客户机上捕获了6个报文，并对第5条报文进行了解析。
| 编号 | 源IP地址 | 目的IP地址 | 报文摘要 | 报文捕获时间 |
| 1 | 192.168.0.1 | 192.168.0.36 |
DHCP:Request, Type:DHCP release
| 09:06:55 |
| 2 | 0.0.0.0 | 255.255.255.255 |
DHCP:Request, Type:DHCP discover
| 09:07:00 |
| 3 | 192.168.0.36 | 255.255.255.255 |
DHCP:Reply, Type:DHCP offer
| 09:07:00 |
| 4 | 0.0.0.0 | 255.255.255.255 |
DHCP:Request, Type:DHCP request
| 09:07:00 |
| 5 | 192.168.0.36 | 255.255.255.255 |
DHCP:Reply, Type:DHCP ack
| 09:07:00 |
| 6 | 192.168.0.1 | 192.168.0.47 | WINS: C ID=33026 op=register name=xp | 09:07:03 |
|
DHCP: ----- DHCP Header -----
DHCP: Boot record type = 2 (Reply)
DHCP: Hardware address type = 1 (10M Ethernet)
DHCP: Hardware address length = 6 bytes
DHCP:
DHCP: Hops = 0
DHCP: Transaction id = 2219131D
DHCP: Elapsed boot time = 0 seconds
DHCP: Flags = 0000
DHCP: 0 = no broadcast
DHCP: Client self-assigned address = [0.0.0.0]
DHCP: Client address = [192.168.0.1]
DHCP: Next Server to use in bootstrap = [0.0.0.0]
DHCP: Relay Agent = [0.0.0.0]
DHCP: Client hardware address = 001122334455
DHCP:
DHCP: Host name = ""
DHCP: Boot file name = ""
DHCP:
DHCP: Vendor Information tag = 63825363
DHCP: Message Type = 5 (DHCP Ack)
DHCP: Address renewel interval = 345600 (seconds)
DHCP: Address rebinding interval = 604800 (seconds)
DHCP: Request
IP Address lease time = 691200 (seconds)
DHCP: Subnet mask = 255.255.255.0
DHCP: Gateway address = [192.168.0.100]
DHCP: Domain Name Server address = [202.106.0.20] |
分析图中信息并回答下列问题。
（1）该客户机获取的IP地址是 [198.168.0.1]
我们可以观察到“Type:DHCP release”就因该明白对应的是第一个步骤左边的就是客户端地址。
（2）在DHCP服务器中设置的DNS服务器地址是 [202.106.0.20]，设置的路由器地址是 [192.168.0.100]。
“Domain Name Server”的缩写就是DSN（域名服务器地址，DNS服务器的ip地址）；“Gateway address ”就是网关地址，缺省路由（客户机直连的路由器）的ip地址。
（3）若该客户机由DHCP服务器分配固定的IP地址，则在新建保留时，需输入的MAC地址是 [001122334455]。
“Client hardware address” 指的就是客户机的物理地址（MAC地址）
（4）DHCP服务器的IP地址是 [192.168.0.36]。
我们可以观察到“Type:DHCP release”就因该明白对应的是第一个步骤左边的就是DHCP服务器的IP地址。
例三{无忧/4}
某公司网络DHCP服务器地址为192.168.0.2，可分配IP地址为192.168.0.6-192.168.0.254，缺省网关的地址为192.168.0.1。网络中某客户机从服务器获取IP地址后，在客户机上执行ping www.bupt.edu.cn命令的过程中，连续捕获的5条报文及对第5条报文的部分解析如下图所示。请补全图中空白处的信息。
| 编号 | 源IP地址 | 目的IP地址 | 报文摘要 |
| 1 | 192.168.0.6 | 192.168.0.3 | Dns:Query |
| 2 | [1] | [2] | Dns:Response |
| 3 | 192.168.0.6 | 114.255.40.66 | Ping:Request |
| 4 | 192.168.0.6 | 192.168.0.2 |
DHCP:Request, Type: Request
|
| 5 | [3] | [4] |
DHCP:Reply, Type:Ack
|
|
DHCP: ----- DHCP Header -----
DHCP: Boot record type = 2 (Reply)
DHCP: Hardware address type = 1 (10M Ethernet)
DHCP: Hardware address length = 6 bytes
DHCP: Client self-assigned address = [192.168.0.6]
DHCP: Client address = [192.168.0.6]
DHCP: Next Server to use in bootstrap = [0.0.0.0]
DHCP: Relay Agent = [0.0.0.0]
DHCP: Client hardware address = 001122334455
DHCP: Vendor Information tag = 63825363
DHCP: Message Type = 5
DHCP: Address renewel interval = 345600 (seconds)
DHCP: Address rebinding interval = 604800 (seconds)
DHCP: Request
IP Address lease time = 691200 (seconds)
DHCP: Subnet mask = 255.255.255.0
DHCP: Gateway address = [192.168.0.1]
DHCP: Domain Name Server address = [ [5]]
|
[1]192.168.0.3
[2]192.168.0.6
[3]192.168.0.2
[4]192.168.0.6
[5]192.168.0.3为啥
