IPv4 - DHCP

課程影片

Introduction to DHCP (with demos in Linux)

Image Not Showing Possible Reasons
  • The image file may be corrupted
  • The server hosting the image is unavailable
  • The image path is incorrect
  • The image format is not supported
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第 7LMN 講 路由器運作原理以及網路互連技術 L07 12 13 14

Image Not Showing Possible Reasons
  • The image file may be corrupted
  • The server hosting the image is unavailable
  • The image path is incorrect
  • The image format is not supported
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Lec36 計算機網路 第四章 Internet Protocol Layer (10/19)

Image Not Showing Possible Reasons
  • The image file may be corrupted
  • The server hosting the image is unavailable
  • The image path is incorrect
  • The image format is not supported
Learn More →

目標:動態地分配 IP 位址

現在已經有分配一個網段的 IP 了,問題就是哪台機器要拿哪個 IP?

DHCP 封包格式

取自 RFC2131

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     op (1)    |   htype (1)   |   hlen (1)    |   hops (1)    |
   +---------------+---------------+---------------+---------------+
   |                            xid (4)                            |
   +-------------------------------+-------------------------------+
   |           secs (2)            |           flags (2)           |
   +-------------------------------+-------------------------------+
   |                          ciaddr  (4)                          |
   +---------------------------------------------------------------+
   |                          yiaddr  (4)                          |
   +---------------------------------------------------------------+
   |                          siaddr  (4)                          |
   +---------------------------------------------------------------+
   |                          giaddr  (4)                          |
   +---------------------------------------------------------------+
   |                                                               |
   |                          chaddr  (16)                         |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+
   |                                                               |
   |                          sname   (64)                         |
   +---------------------------------------------------------------+
   |                                                               |
   |                          file    (128)                        |
   +---------------------------------------------------------------+
   |                                                               |
   |                          options (variable)                   |
   +---------------------------------------------------------------+