填空题某客户端使用DHCP获取IP地址等信息，其获取IP地址过程中捕获的4条报文及对第二条报文分析如下图所示。请分析其中的信息，补全内容。
编号报文摘要
1 DHCP:Request，Typc:DHCP discover
2 DHCP:Reply，Type:DHCP 1
3 DHCP:Request，Typc:DHCP Request
4 DHCP:Reply，Type:DHCP ACK
DLC：- - - - -DLC Header - - - - -
DLC：Destination 2
DLC：source=001122334455
DLC：Ethertype=0800(IP)
IP：D= 3，S=192.168.0.1
4:D=68，S=67
DHCP:- - - - -DHCP Header - - - - -
DHCP:Boot record type =2(Reply)
DHCP:Hardware address type =1(10M Ethernet)
DHCP:Hardware address length =6 Bytes
DHCP:Hops =0
DHCP:Transaction id =6019121F
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=[192.168.0.180]
DHCP:Next Server to use in bootstrap=[0.0.0.0]
DHCP:Relay Agent=[0.0.0.0]
DHCP:Client hardware address=001234567890
DHCP:Host name=“”
DHCP:Boot file name=“”
DHCP:Vendor Information tag=53825276
DHCP:Message Type=2
DHCP:Address renewel interval=345600 (seconds)
DHCP:Address rebinding interval=604800(seconds)
DHCP:Request IP Address leased time=691200 (seconds)
DHCP:Sever IP Address= 5
DHCP:Subnet mask=255.255.255.0
DHCP:Gateway address=[192.168.0.100]
DHCP:Domain Name Server address=[202.106.0.100]

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【正确答案】 1、**unknown, 2、**unknown, 3、**unknown, 4、**unknown, 5、**unknown

【答案解析】192.168.0.1 [解析] 第二条报文是DHCP服务器广播的DHCP offer消息，源IP地址为DHCP服务器IP地址，即为192.168.0.1。
DHCP的工作原理：(1)DHCP客户端广播“DHCP发现”消息，该消息源地址为0.0.0.0，目的地址为255.255.255.255。(2)当DHCP服务器监听到客户端的“DHCP发现”消息时，它会从还没有租出的地址中选择最前面的空置IP，连同其他的TCP/IP设定，向网络中广播“DHCP供给”消息。(3)DHCP客户端收到“DHCP供给”消息，如果接受其中提供的参数，就通过广播“DHCP请求”消息向DHCP服务器请求提供IP地址。(4)DHCP服务器广播“DHCP确认”消息，将IP地址分配给DHCP客户机。