■ 概要
動(dòng)態(tài)主機(jī)配置協(xié)議 (DHCP) 是 RFC 1541（由 RFC 2131 替代）定義的標(biāo)準(zhǔn)協(xié)議，該協(xié)議允許服務(wù)器向客戶端動(dòng)態(tài)分配 IP 地址和配置信息。 通常，DHCP 服務(wù)器至少給客戶端提供以下基本信息：
IP 地址
子網(wǎng)掩碼
默認(rèn)網(wǎng)關(guān)
它還可以提供其它信息，如域名服務(wù) (DNS) 服務(wù)器地址和 Windows Internet 命名服務(wù) (WINS) 服務(wù)器地址。 系統(tǒng)管理員配置 DHCP 服務(wù)器分配給客戶端的選項(xiàng)。
■ 更多信息
以下 Microsoft 產(chǎn)品提供 DHCP 客戶端功能：
Windows NT Server 3.5、3.51 和 4.0
Windows NT Workstation 3.5、3.51 和 4.0
Windows 95
Microsoft Network Client 3.0 for MS-DOS
Microsoft LAN Manager Client 2.2c for MS-DOS
Microsoft TCP/IP-32 for Windows for Workgroups 3.11、3.11a 和 3.11b
DHCP 客戶端可以接收來(lái)自 DHCP 服務(wù)器的選項(xiàng)，而不同的 DHCP 客戶端支持不同的這些選項(xiàng)。 有關(guān) Microsoft DHCP 客戶端所支持的特定 DHCP 選項(xiàng)的信息，請(qǐng)參見(jiàn) Microsoft Knowledge Base 中以下文章：
Q121005 受客戶端支持的 DHCP 選項(xiàng)
以下 Microsoft 服務(wù)器操作系統(tǒng)提供 DHCP 服務(wù)器功能：
Windows NT Server 3.5
Windows NT Server 3.51
Windows NT Server 4.0
當(dāng)客戶端被配置為接收 DHCP 信息后首次初始化時(shí)，它將啟動(dòng)一個(gè)與服務(wù)器的對(duì)話。
以下是客戶端和服務(wù)器之間對(duì)話的匯總表，后面是數(shù)據(jù)包級(jí)的過(guò)程說(shuō)明：
Source Dest Source Dest Packet
MAC addr MAC addr IP addr IP addr Description
-----------------------------------------------------------------
Client Broadcast 0.0.0.0 255.255.255.255 DHCP Discover
DHCPsrvr Broadcast DHCPsrvr 255.255.255.255 DHCP Offer
Client Broadcast 0.0.0.0 255.255.255.255 DHCP Request
DHCPsrvr Broadcast DHCPsrvr 255.255.255.255 DHCP ACK
DHCP 客戶端和 DHCP 服務(wù)器之間的詳細(xì)對(duì)話如下：
DHCPDISCOVER
客戶端發(fā)送 DHCPDISCOVER 數(shù)據(jù)包。 以下內(nèi)容摘自網(wǎng)絡(luò)監(jiān)視器的捕獲信息，顯示了 DHCPDISCOVER 數(shù)據(jù)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 部分將數(shù)據(jù)包標(biāo)識(shí)為 Discover 數(shù)據(jù)包，并使用網(wǎng)卡的物理地址在兩處標(biāo)識(shí)客戶端。注意 CHADDR 字段和 DHCP 的值： Client Identifier 字段是相同的。
IP: ID = 0x0; Proto = UDP; Len: 328
IP: Version = 4 (0x4)
IP: Header Length = 20 (0x14)
IP: Service Type = 0 (0x0)
IP: Precedence = Routine
IP: ...0.... = Normal Delay
IP: ....0... = Normal Throughput
IP: .....0.. = Normal Reliability
IP: Total Length = 328 (0x148)
IP: Identification = 0 (0x0)
IP: Flags Summary = 0 (0x0)
IP: .......0 = Last fragment in datagram
IP: ......0. = May fragment datagram if necessary
IP: Fragment Offset = 0 (0x0) bytes
IP: Time to Live = 128 (0x80)
IP: Protocol = UDP - User Datagram
IP: Checksum = 0x39A6
IP: Source Address = 0.0.0.0
IP: Destination Address = 255.255.255.255
IP: 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 Ethernet
DHCP: 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 Broadcast
DHCP: Client IP Address (ciaddr) = 0.0.0.0
DHCP: Your IP Address (yiaddr) = 0.0.0.0
DHCP: Server IP Address (siaddr) = 0.0.0.0
DHCP: Relay IP Address (giaddr) = 0.0.0.0
DHCP: Client Ethernet Address (chaddr) = 08002B2ED85E
DHCP: Server Host Name (sname) =
DHCP: Boot File Name (file) =
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP Discover
DHCP: Client-identifier = (Type: 1) 08 00 2b 2e d8 5e
DHCP: Host Name = JUMBO-WS
DHCP: Parameter Request List = (Length: 7) 01 0f 03 2c 2e 2f 06
DHCP: End of this option field
DHCPOFFER
DHCP 服務(wù)器通過(guò)發(fā)送 DHCPOFFER 數(shù)據(jù)包來(lái)作出響應(yīng)。 在以下摘錄捕獲信息的 IP 部分中，Source 地址現(xiàn)在是 DHCP 服務(wù)器 IP 地址，而 Destination 地址是廣播地址 255.255.255.255。 DHCP 部分將數(shù)據(jù)包標(biāo)識(shí)為 Offer。 YIADDR 字段是用服務(wù)器提供給客戶端的 IP 地址填寫的。 注意，CHADDR 字段依然包含請(qǐng)求客戶端的物理地址。 另外，在 DHCP Option Field 部分，可以看到隨 IP 地址一起由服務(wù)器發(fā)送的各種選項(xiàng)。 在這種情況下，服務(wù)器發(fā)送的是子網(wǎng)掩碼、默認(rèn)網(wǎng)關(guān)（路由器）、租用時(shí)間、WINS 服務(wù)器地址（NetBIOS 名稱服務(wù)）和 NetBIOS 節(jié)點(diǎn)類型。
IP: ID = 0x3C30; Proto = UDP; Len: 328
IP: Version = 4 (0x4)
IP: Header Length = 20 (0x14)
IP: Service Type = 0 (0x0)
IP: Precedence = Routine
IP: ...0.... = Normal Delay
IP: ....0... = Normal Throughput
IP: .....0.. = Normal Reliability
IP: Total Length = 328 (0x148)
IP: Identification = 15408 (0x3C30)
IP: Flags Summary = 0 (0x0)
IP: .......0 = Last fragment in datagram
IP: ......0. = May fragment datagram if necessary
IP: Fragment Offset = 0 (0x0) bytes
IP: Time to Live = 128 (0x80)
IP: Protocol = UDP - User Datagram
IP: Checksum = 0x2FA8
IP: Source Address = 157.54.48.151
IP: Destination Address = 255.255.255.255
IP: Data: Number of data bytes remaining = 308 (0x0134)
DHCP: Offer (xid=21274A1D)
DHCP: Op Code (op) = 2 (0x2)
DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet
DHCP: 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 Broadcast
DHCP: Client IP Address (ciaddr) = 0.0.0.0
DHCP: Your IP Address (yiaddr) = 157.54.50.5
DHCP: Server IP Address (siaddr) = 0.0.0.0
DHCP: Relay IP Address (giaddr) = 0.0.0.0
DHCP: Client Ethernet Address (chaddr) = 08002B2ED85E
DHCP: Server Host Name (sname) =
DHCP: Boot File Name (file) =
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP Offer
DHCP: Subnet Mask = 255.255.240.0
DHCP: Renewal Time Value (T1) = 8 Days, 0:00:00
DHCP: Rebinding Time Value (T2) = 14 Days, 0:00:00
DHCP: IP Address Lease Time = 16 Days, 0:00:00
DHCP: Server Identifier = 157.54.48.151
DHCP: Router = 157.54.48.1
DHCP: NetBIOS Name Service = 157.54.16.154
DHCP: NetBIOS Node Type = (Length: 1) 04
DHCP: End of this option field
動(dòng)態(tài)主機(jī)配置協(xié)議 (DHCP) 是 RFC 1541（由 RFC 2131 替代）定義的標(biāo)準(zhǔn)協(xié)議，該協(xié)議允許服務(wù)器向客戶端動(dòng)態(tài)分配 IP 地址和配置信息。 通常，DHCP 服務(wù)器至少給客戶端提供以下基本信息：
IP 地址
子網(wǎng)掩碼
默認(rèn)網(wǎng)關(guān)
它還可以提供其它信息，如域名服務(wù) (DNS) 服務(wù)器地址和 Windows Internet 命名服務(wù) (WINS) 服務(wù)器地址。 系統(tǒng)管理員配置 DHCP 服務(wù)器分配給客戶端的選項(xiàng)。
■ 更多信息
以下 Microsoft 產(chǎn)品提供 DHCP 客戶端功能：
Windows NT Server 3.5、3.51 和 4.0
Windows NT Workstation 3.5、3.51 和 4.0
Windows 95
Microsoft Network Client 3.0 for MS-DOS
Microsoft LAN Manager Client 2.2c for MS-DOS
Microsoft TCP/IP-32 for Windows for Workgroups 3.11、3.11a 和 3.11b
DHCP 客戶端可以接收來(lái)自 DHCP 服務(wù)器的選項(xiàng)，而不同的 DHCP 客戶端支持不同的這些選項(xiàng)。 有關(guān) Microsoft DHCP 客戶端所支持的特定 DHCP 選項(xiàng)的信息，請(qǐng)參見(jiàn) Microsoft Knowledge Base 中以下文章：
Q121005 受客戶端支持的 DHCP 選項(xiàng)
以下 Microsoft 服務(wù)器操作系統(tǒng)提供 DHCP 服務(wù)器功能：
Windows NT Server 3.5
Windows NT Server 3.51
Windows NT Server 4.0
當(dāng)客戶端被配置為接收 DHCP 信息后首次初始化時(shí)，它將啟動(dòng)一個(gè)與服務(wù)器的對(duì)話。
以下是客戶端和服務(wù)器之間對(duì)話的匯總表，后面是數(shù)據(jù)包級(jí)的過(guò)程說(shuō)明：
Source Dest Source Dest Packet
MAC addr MAC addr IP addr IP addr Description
-----------------------------------------------------------------
Client Broadcast 0.0.0.0 255.255.255.255 DHCP Discover
DHCPsrvr Broadcast DHCPsrvr 255.255.255.255 DHCP Offer
Client Broadcast 0.0.0.0 255.255.255.255 DHCP Request
DHCPsrvr Broadcast DHCPsrvr 255.255.255.255 DHCP ACK
DHCP 客戶端和 DHCP 服務(wù)器之間的詳細(xì)對(duì)話如下：
DHCPDISCOVER
客戶端發(fā)送 DHCPDISCOVER 數(shù)據(jù)包。 以下內(nèi)容摘自網(wǎng)絡(luò)監(jiān)視器的捕獲信息，顯示了 DHCPDISCOVER 數(shù)據(jù)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 部分將數(shù)據(jù)包標(biāo)識(shí)為 Discover 數(shù)據(jù)包，并使用網(wǎng)卡的物理地址在兩處標(biāo)識(shí)客戶端。注意 CHADDR 字段和 DHCP 的值： Client Identifier 字段是相同的。
IP: ID = 0x0; Proto = UDP; Len: 328
IP: Version = 4 (0x4)
IP: Header Length = 20 (0x14)
IP: Service Type = 0 (0x0)
IP: Precedence = Routine
IP: ...0.... = Normal Delay
IP: ....0... = Normal Throughput
IP: .....0.. = Normal Reliability
IP: Total Length = 328 (0x148)
IP: Identification = 0 (0x0)
IP: Flags Summary = 0 (0x0)
IP: .......0 = Last fragment in datagram
IP: ......0. = May fragment datagram if necessary
IP: Fragment Offset = 0 (0x0) bytes
IP: Time to Live = 128 (0x80)
IP: Protocol = UDP - User Datagram
IP: Checksum = 0x39A6
IP: Source Address = 0.0.0.0
IP: Destination Address = 255.255.255.255
IP: 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 Ethernet
DHCP: 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 Broadcast
DHCP: Client IP Address (ciaddr) = 0.0.0.0
DHCP: Your IP Address (yiaddr) = 0.0.0.0
DHCP: Server IP Address (siaddr) = 0.0.0.0
DHCP: Relay IP Address (giaddr) = 0.0.0.0
DHCP: Client Ethernet Address (chaddr) = 08002B2ED85E
DHCP: Server Host Name (sname) =
DHCP: Boot File Name (file) =
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP Discover
DHCP: Client-identifier = (Type: 1) 08 00 2b 2e d8 5e
DHCP: Host Name = JUMBO-WS
DHCP: Parameter Request List = (Length: 7) 01 0f 03 2c 2e 2f 06
DHCP: End of this option field
DHCPOFFER
DHCP 服務(wù)器通過(guò)發(fā)送 DHCPOFFER 數(shù)據(jù)包來(lái)作出響應(yīng)。 在以下摘錄捕獲信息的 IP 部分中，Source 地址現(xiàn)在是 DHCP 服務(wù)器 IP 地址，而 Destination 地址是廣播地址 255.255.255.255。 DHCP 部分將數(shù)據(jù)包標(biāo)識(shí)為 Offer。 YIADDR 字段是用服務(wù)器提供給客戶端的 IP 地址填寫的。 注意，CHADDR 字段依然包含請(qǐng)求客戶端的物理地址。 另外，在 DHCP Option Field 部分，可以看到隨 IP 地址一起由服務(wù)器發(fā)送的各種選項(xiàng)。 在這種情況下，服務(wù)器發(fā)送的是子網(wǎng)掩碼、默認(rèn)網(wǎng)關(guān)（路由器）、租用時(shí)間、WINS 服務(wù)器地址（NetBIOS 名稱服務(wù)）和 NetBIOS 節(jié)點(diǎn)類型。
IP: ID = 0x3C30; Proto = UDP; Len: 328
IP: Version = 4 (0x4)
IP: Header Length = 20 (0x14)
IP: Service Type = 0 (0x0)
IP: Precedence = Routine
IP: ...0.... = Normal Delay
IP: ....0... = Normal Throughput
IP: .....0.. = Normal Reliability
IP: Total Length = 328 (0x148)
IP: Identification = 15408 (0x3C30)
IP: Flags Summary = 0 (0x0)
IP: .......0 = Last fragment in datagram
IP: ......0. = May fragment datagram if necessary
IP: Fragment Offset = 0 (0x0) bytes
IP: Time to Live = 128 (0x80)
IP: Protocol = UDP - User Datagram
IP: Checksum = 0x2FA8
IP: Source Address = 157.54.48.151
IP: Destination Address = 255.255.255.255
IP: Data: Number of data bytes remaining = 308 (0x0134)
DHCP: Offer (xid=21274A1D)
DHCP: Op Code (op) = 2 (0x2)
DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet
DHCP: 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 Broadcast
DHCP: Client IP Address (ciaddr) = 0.0.0.0
DHCP: Your IP Address (yiaddr) = 157.54.50.5
DHCP: Server IP Address (siaddr) = 0.0.0.0
DHCP: Relay IP Address (giaddr) = 0.0.0.0
DHCP: Client Ethernet Address (chaddr) = 08002B2ED85E
DHCP: Server Host Name (sname) =
DHCP: Boot File Name (file) =
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP Offer
DHCP: Subnet Mask = 255.255.240.0
DHCP: Renewal Time Value (T1) = 8 Days, 0:00:00
DHCP: Rebinding Time Value (T2) = 14 Days, 0:00:00
DHCP: IP Address Lease Time = 16 Days, 0:00:00
DHCP: Server Identifier = 157.54.48.151
DHCP: Router = 157.54.48.1
DHCP: NetBIOS Name Service = 157.54.16.154
DHCP: NetBIOS Node Type = (Length: 1) 04
DHCP: End of this option field