题目：
某客户机使用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2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,Type:DHCP discover
2 DHCP:Reply,Type:DHCP ______
3 DHCP:Request,Typc:DHCP Request
4 DHCP:Reply,Type:DHCP ACK
DLC:----- DLC Header-----
DLC:Destination=______
DLC:Source=001122334455
DLC:Ethertype=0800(IP)
IP:D=______,S=192.168.0.1
______:D=68,S=67
DHCP:-----DHCP Header-----
DHCP:Boot record type =2(Reply)
DHCP:Hardware address type =1(10M Ethemet)
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(seeonds)
DHCP:Address rebinding interval=604800(seconds)
DHCP:Request IP Address leased time=691200(seconds)
DHCP:Sever IP Address=______
DHCP:Subnet mask=255.255.255.0
DHCP:Gateway address=[192.168.0.100]
DHCP:Domain Name Server address=[202.106.0.100]
答案：
参考答案：255.255.255.255
解析： 第2条报文是DHCP服务器广播的DHCP offer消息，源IP地址为DHCP服务器地址192.168.0.1；目的IP地址为广播地址255.255.255.255。所以应填入：255.255.255.255。
