شیوه آی پی دهی dhcp به کلاینت ها

[mansoor66]

با سلام .
dhcp چگونه به کلاینت ها آی پی می ده و یا کلاینت ها چگونه از dhcp آی پی دریافت می کنند ؟؟؟

[dana1975]

فرض کن که ۲ تا شبکه مختلف داری و یه سرور که اونم با ۲ تا کارت شبکه مجزا به هر ۲ تا شبکه وصله
رو سرور ۲ تا اسکوپ تعریف میکنی* که رنجش با رنج IP *های کارت شبکه سرورت یکی* باشه
بد هر یوزر که درخواست IP میفرست بسته به اینکه کدوم کارت شبکه رو ببینه میتونه از سرور IP (و همینطور تنظیماتی که شما رو DHCP تنظیم کردی) رو بگیره

[jahanshahy]

با سلام .
dhcp چگونه به کلاینت ها آی پی می ده و یا کلاینت ها چگونه از dhcp آی پی دریافت می کنند ؟؟؟

منظورتون تنظیم DHCP هست؟ یا درک موضوع!؟

[mansoor66]

با تشکر
دوستان من اینا رو می دونم . من می خوام این قضیه رو مو شکافی کنم واسه درک بهتر . من شیوه عملکرد dhcp را می خوام . اینکه چطوری به سیستم آی پی میده .

[Dj Pashmak]

As soon as a DHCP Offer message is received, the client selects the offered address by replying to the server with a DHCP Request message.

Typically, the offering server sends a DHCP Acknowledgment (DHCP ACK) message approving the lease. (DHCP options information is included in the acknowledgment.)

Once the client receives acknowledgment, it configures its Transmission Control Protocol/Internet Protocol (TCP/IP) properties using the information in the reply and joins the network.

[mansoor66]

تمام این صحبت ها درست . اما میشه یکم واضح تر توضیح بدید ؟؟ مثلاً این پیغام هایی که رد و بدل میشه و نهایتا منجر به اختصاص آی پی می شه حاوی چه اطلاعاتی است ؟ این مفهوم برادکست کردن توی این قضیه چی هست ؟؟؟(یه جا یه مطلبی خوندم که اینو توش نوشته بود )

[mansoor66]

آقا من این پست قبلی را در جواب یکی از دوستان که لطف کرده بود و پاسخ داده بودند دادم . اما الان می بینم هیچ اثری ازون پست نیست !!!!!!!!!!!! تو رو خدا فکر نکنین من با خودم حرف نی میزنم ! . بابا همین الان پستشو دیدم !!!!!!!!!!!! کجا رفت یهو ؟؟

[Hakimi]

DHCP (Dynamic Host Configuration Protocol) Basics


When a client is initialized for the first time after it is configured to receive DHCP information, it initiates a conversation with the server.

Below is a summary table of the conversation between client and server, which is followed by a packet-level description of the process:

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



The detailed conversation between DHCP client and DHCP server is as follows:

DHCPDISCOVER

The client sends a DHCPDISCOVER packet. The following is an excerpt from a network monitor capture showing the IP and DHCP portions of a DHCPDISCOVER packet. In the IP section, you can see the Destination address is 255.255.255.255 and the Source address is 0.0.0.0. The DHCP section identifies the packet as a Discover packet and identifies the client in two places using the physical address of the network card. Note the values in the CHADDR field and the DHCP: Client Identifier field are identical.
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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
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

The DHCP server responds by sending a DHCPOFFER packet. In the IP section of the capture excerpt below, the Source address is now the DHCP server IP address, and the Destination address is the broadcast address 255.255.255.255. The DHCP section identifies the packet as an Offer. The YIADDR field is populated with the IP address the server is offering the client. Note the CHADDR field still contains the physical address of the requesting client. Also, we see in the DHCP Option Field section the various options being sent by the server along with the IP address. In this case the server is sending the Subnet Mask, Default Gateway (Router), Lease Time, WINS server address (NetBIOS Name Service), and the NetBIOS Node Type.
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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
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



DHCPREQUEST

The client responds to the DHCPOFFER by sending a DHCPREQUEST. In the IP section of the capture below, the Source address of the client is still 0.0.0.0 and the Destination for the packet is still 255.255.255.255. The client retains 0.0.0.0 because the client hasn't received verification from the server that it's okay to start using the address offered. The Destination is still broadcast, because more than one DHCP server may have responded and may be holding a reservation for an Offer made to the client. This lets those other DHCP servers know they can release their offered addresses and return them to their available pools. The DHCP section identifies the packet as a Request and verifies the offered address using the DHCP: Requested Address field. The DHCP: Server Identifier field shows the IP address of the DHCP server offering the lease.
IP: ID = 0x100; 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 = 256 (0x100)
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 = 0x38A6
IP: Source Address = 0.0.0.0
IP: Destination Address = 255.255.255.255
IP: Data: Number of data bytes remaining = 308 (0x0134)

DHCP: Request (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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP Request
DHCP: Client-identifier = (Type: 1) 08 00 2b 2e d8 5e
DHCP: Requested Address = 157.54.50.5
DHCP: Server Identifier = 157.54.48.151
DHCP: Host Name = JUMBO-WS
DHCP: Parameter Request List = (Length: 7) 01 0f 03 2c 2e 2f 06
DHCP: End of this option field



DHCPACK

The DHCP server responds to the DHCPREQUEST with a DHCPACK, thus completing the initialization cycle. The Source address is the DHCP server IP address, and the Destination address is still 255.255.255.255. The YIADDR field contains the client's address, and the CHADDR and DHCP: Client Identifier fields are the physical address of the network card in the requesting client. The DHCP Option section identifies the packet as an ACK.
IP: ID = 0x3D30; 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 = 15664 (0x3D30)
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 = 0x2EA8
IP: Source Address = 157.54.48.151
IP: Destination Address = 255.255.255.255
IP: Data: Number of data bytes remaining = 308 (0x0134)

DHCP: ACK (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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP ACK
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: Subnet Mask = 255.255.240.0
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



If the client has previously had a DHCP assigned IP address and it is restarted, the client will specifically request the previously leased IP address in a special DHCPREQUEST packet. The Source address is 0.0.0.0 and the Destination is the broadcast address 255.255.255.255. Microsoft clients will populate the DHCP Option Field DHCP: Requested Address with the previously assigned address. Strictly RFC compliant clients will populate the CIADDR Field with the address requested. The Microsoft DHCP server will accept either.
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: Request (xid=2757554E)
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) = 660034894 (0x2757554E)
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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP Request
DHCP: Client-identifier = (Type: 1) 08 00 2b 2e d8 5e
DHCP: Requested Address = 157.54.50.5
DHCP: Host Name = JUMBO-WS
DHCP: Parameter Request List = (Length: 7) 01 0f 03 2c 2e 2f 06
DHCP: End of this option field



At this point, the server may or may not respond. The behavior of the Windows NT DHCP server depends on the version of the operating system being used as well as other factors such as superscoping. If the server determines that the client can still use the address, it will either remain silent or ACK the DHCPREQUEST. If the server determines that the client cannot have the address, it will send a NACK.
IP: ID = 0x3F1A; 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 = 16154 (0x3F1A)
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 = 0x2CBE
IP: Source Address = 157.54.48.151
IP: Destination Address = 255.255.255.255
IP: Data: Number of data bytes remaining = 308 (0x0134)

DHCP: NACK (xid=74A005CE)
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) = 1956644302 (0x74A005CE)
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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
DHCP: Magic Cookie = [OK]
DHCP: Option Field (options)
DHCP: DHCP Message Type = DHCP NACK
DHCP: Server Identifier = 157.54.48.151
DHCP: End of this option field



The client will then begin the discover process, but the DHCPDISCOVER packet will still attempt to lease the same address. In many instances, tth client will get the same address but may not.
IP: ID = 0x100; 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 = 256 (0x100)
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 = 0x38A6
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=3ED14752)
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) = 1053902674 (0x3ED14752)
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) = <Blank>
DHCP: Boot File Name (file) = <Blank>
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: Requested Address = 157.54.51.5
DHCP: Host Name = JUMBO-WS
DHCP: Parameter Request List = (Length: 7) 01 0f 03 2c 2e 2f 06
DHCP: End of this option field



DHCP information obtained by the client from a DHCP server will have a lease time associated with it. The lease time defines how long the client can use the DHCP-assigned information. When the lease reaches certain milestones, the client will attempt to renew its DHCP information.

Source: DHCP &#40;Dynamic Host Configuration Protocol&#41; Basics

[Dj Pashmak]

The DHCP client broadcasts a DHCP Discover message to the local subnet

ابتدا کلاینتی که میخواد از سرور IP بگیره پیامهایی رو برای شناخت DHCP Serverها ارسال میکنه

A DHCP server can respond with a DHCP Offer message that contains an offered
IP address for lease to the client

در این مرحله DHCP Server با یک پیغام DHCP Offer که حاوی IP پیشنهادی به کلاینت هست جواب میده

As soon as a DHCP Offer message is received, the client selects the offered address by replying to the server with a DHCP Request message

بلافاصله بعد از اینکه پیغام DHCP Offer سرور توسط کلاینت دریافت شد،کلاینت IP پیشنهادی رو با فرستادن پیفام DHCP Request انتخاب میکنه.

Typically, the offering server sends a DHCP Acknowledgment (DHCP ACK) message (approving the lease. (DHCP options information is included in the acknowledgment

DHCP Server با فرستادن پیغام تایید IP داده شده رو تایید میکنه و کلاینت تنظیمات مربوطه رو با همین پیغام تبریک میگیره

امیدوارم منظور رو گرفته باشین اما برای توضیح کامل و جامع میتونید به فصل 8 کتاب 291-70
مراجعه کنید

[Dj Pashmak]

آقا من این پست قبلی را در جواب یکی از دوستان که لطف کرده بود و پاسخ داده بودند دادم . اما الان می بینم هیچ اثری ازون پست نیست !!!!!!!!!!!! تو رو خدا فکر نکنین من با خودم حرف نی میزنم ! . بابا همین الان پستشو دیدم !!!!!!!!!!!! کجا رفت یهو ؟؟

اون پست رو من خواستم مرتب و تکمیل کنم حذفش کردم گویا مجددا گذاشتنش.

توضیح جناب حکیمی و لینکی که دادن گویا ترین پاسخه.اما باز هم میتونید به کتاب 291-70 فصل 8 برای مطالعه رجوع کنید

[mansoor66]

نمیشه خلاصه تر و گویا تر ، یک نفر این قضیه را عامیانه ، واسه من بی سواد توضیح بده ؟ !

[jahanshahy]

نمیشه خلاصه تر و گویا تر ، یک نفر این قضیه را عامیانه ، واسه من بی سواد توضیح بده ؟ !

ببین دوست من برادکست کردن یعنی داد زدن توی شبکه

وقتی شما Connection تون رو فعال میکنید این اتفاق میفته:
1.کامپیوتر شما داد میزنه که آهای......کی آی پی توزیع مکنه..
2.اگه DHCP داشته باشین اون کامپیوتر به کامپیوتر شما میگه من دارم می خوای!!!
3.کامپیوتر شما هم که مشتاق گرفتن هست میگه یکی به من بده!!!!
4. DHCP Server یه آی پی به شما میده که توی شبکه بیاین!!!

خودم هم کف کردم با این توضیح

[Ronin]

توی DHCP وقتی یه کلاینت IP گرفت اگه بر فرض خاموش بشه و 3 روز دیگه بیاد دوباره همون IP و میگیره
این با تئوریش درست در نمیاد که هر دفعه وصل شد یه IP بگیره
وقتی هم سرور IP میده از آخرین IP تو رنج تنظیم شده شوع می کنه میاد پایین
این که تجربه منه حالا این همه تئوری نمی دونم چیه ؟!

[jahanshahy]

توی DHCP وقتی یه کلاینت IP گرفت اگه بر فرض خاموش بشه و 3 روز دیگه بیاد دوباره همون IP و میگیره
این با تئوریش درست در نمیاد که هر دفعه وصل شد یه IP بگیره
وقتی هم سرور IP میده از آخرین IP تو رنج تنظیم شده شوع می کنه میاد پایین
این که تجربه منه حالا این همه تئوری نمی دونم چیه ؟!

اگه lease time بالا باشه گفته شما درسته ولی برای یه محیط مثل دانشگاه که کلاینت وایرلس و درخواست زیاد داره و lease رو هم معمولاً روی یک ساعت تنظیم میکنند این برداشت اشتباهه...صبح تا عصر آی پی ممکنه عوض بشه.
هنگام توزیع هم از ابتدای رنج توزیع میشه...تجربه ای که من تا حالا داشتم

[Naderpour]

توی DHCP وقتی یه کلاینت IP گرفت اگه بر فرض خاموش بشه و 3 روز دیگه بیاد دوباره همون IP و میگیره
این با تئوریش درست در نمیاد که هر دفعه وصل شد یه IP بگیره
وقتی هم سرور IP میده از آخرین IP تو رنج تنظیم شده شوع می کنه میاد پایین
این که تجربه منه حالا این همه تئوری نمی دونم چیه ؟!

هر IP یک مقدار Lease Time داره که بعد از گذشت این زمان سیستم دوباره برای گرفتن IP جدید به Dhcp server درخواست می ده ، اگر بعد از گذشتن این زمان سرور درخواستی از سمت Client دریافت نکنه امکان داره ip رو به یک سیستم دیگه اختصاص بده.در ضمن این امکان هم وجود داره که در درخواست مجدد ، سرور IP قبلی رو به Client اختصاص نده .

نحوه اختصاص ip هم بستگی به سرور داره .