DHCP进程.docx

DHCP进程SourceDest SourceDest PacketMAC addr MAC addr IP addr IP addr Description-----------------------------------------------------------------Client Broadcast 0.0.0.0 255.255.255.255 DHCP DiscoverDHCPsrvr BroadcastDHCPsrvr 255.255.255.255 DHCP OfferClient Broadcast 0.0.0.0 255.255.255.255 DHCP RequestDHCPsrvr BroadcastDHCPsrvr 255.255.255.255 DHCP ACKDHCP 客户端和 DHCP 服务器之间的详细对话如下：DHCPDISCOVER客户端发送 DHCPDISCOVER 数据包。以下内容摘自网络监视器的捕获信息，显示了 DHCPDISCOVER 数据包中的 IP 和 DHCP 部分。在 IP 部分，可以看到 Destination 地址是 255.255.255.255，而 Source 地址是 0.0.0.0。DHCP 部分将数据包标识为 Discover 数据包，并使用网卡的物理地址在两处标识客户端。注意 CHADDR 字段和 DHCP 中的值：Client Identifier 字段是相同的。IP:ID = 0x0; Proto = UDP; Len: 328IP:Version = 4 (0x4)IP:Header Length = 20 (0x14)IP:Service Type = 0 (0x0)IP:Precedence = RoutineIP:...0.... = Normal DelayIP:....0... = Normal ThroughputIP:.....0.. = Normal ReliabilityIP:Total Length = 328 (0x148)IP:Identification = 0 (0x0)IP:Flags Summary = 0 (0x0)IP:.......0 = Last fragment in datagramIP:......0. = May fragment datagram if necessaryIP:Fragment Offset = 0 (0x0) bytesIP:Time to Live = 128 (0x80)IP:Protocol = UDP - User DatagramIP:Checksum = 0x39A6IP:Source Address = 0.0.0.0IP:Destination Address = 255.255.255.255IP:Data:Number of data bytes remaining = 308 (0x0134)DHCP:Discover (xid=21274A1D)DHCP:Op Code (op) = 1 (0x1)DHCP:Hardware Type (htype) = 1 (0x1) 10Mb EthernetDHCP:Hardware Address Length (hlen) = 6 (0x6)DHCP:Hops (hops) = 0 (0x0)DHCP:Transaction ID (xid) = 556223005 (0x21274A1D)DHCP:Seconds (secs) = 0 (0x0)DHCP:Flags (flags) = 0 (0x0)DHCP:0............... = No BroadcastDHCP:Client IP Address (ciaddr) = 0.0.0.0DHCP:Your IP Address (yiaddr) = 0.0.0.0DHCP:Server IP Address (siaddr) = 0.0.0.0DHCP:Relay IP Address (giaddr) = 0.0.0.0DHCP:Client Ethernet Address (chaddr) = 08002B2ED85EDHCP:Server Host Name (sname) = BlankDHCP:Boot File Name (file) = BlankDHCP:Magic Cookie = [OK]DHCP:Option Field (options)DHCP:DHCP Message Type