Slide Note
0 likes | 12 Views
The provided content explains the packet formats and fields involved in DHCP (Dynamic Host Configuration Protocol) Request and Reply packets. It breaks down the components such as IP header, UDP header, DHCP header, and various fields within these headers. Detailed information is provided on the purpose and significance of each field, including version, DSCP, ECN, Total Length, Identification, Flags, Fragment Offset, Time to Live, Protocol, Header Checksum, and more. The content also includes sample values for these fields in both a DHCP Request packet and a DHCP Reply packet.
E N D
DHCP 封包格式 指導教授：許蒼嶺 博士 研究生：洪玟碩
DHCP Request 封包 IP header與UDP header Version IHL DSCP ECN Total Length 0100 0101 101110 11 0000000010000100 Identification Flags Fragment Offset 0000000000000000 010 0000000000000 Time to Live Protocol Header Checksum IP 01000000 00010001 0100010100100110 Source IP Address 00000000000000000000000000000000 Destination IP Address 11111111111111111111111111111111 Source Port Destination Port 0000000001000100 0000000001000011 UDP Length Checksum 0000000000110000 0000000000110111 Version: 表示 IP 封包的版本 IHL: 表示 IP 封包標頭的長度 DSCP: 優先級分類為三種EF、AF、BSF 從左到右由優先級高變低 ECN: 擁塞通知，11表示擁塞 Total Length: 封包的總長度，包括封包標頭及資料 的長度 Identification: 資料分割後使用的辨識碼 Flags: 格式為 ”0DM” D表示是否可分段，1表示不可 分段，M表示是否有更多分段，0表示最後資料 Fragment Offset: 這段資料在原始資料中所在的位址 Time to Live: 表示封包能經過的 Router 數量 Protocol: 表示該 IP 封包的後續協定 Header Checksum: 標頭檔的錯誤檢查碼 • • • • • • • • • • •
DHCP Request 封包 DHCP header OP HTYPE HLEN HOPS 00000001 00000001 00000110 00100000 Transaction ID 00000000000000000000000011111111 Seconds Flags 0000000000000001 0000000000000001 Client IP Address(ciaddr) 00000000000000000000000000000000 You IP Address(yiaddr) 00000000000000000000000000000000 DHCP Server IP Address(siaddr) 00000000000000000000000000000000 Gateway IP Address(giaddr) 00000000000000000000000000000000 Client Hardware Address(chaddr) 11110000111100001111000011110000 Server Name(sname) 00000000000000000000000000000000 File Name 00000000000000000000000000000000
DHCP Reply 封包 IP header與UDP header Version IHL DSCP ECN Total Length 0100 0101 101110 11 0000000010000100 Identification Flags Fragment Offset 0000000000000000 010 0000000000000 Time to Live Protocol Header Checksum IP 01000000 00010001 0100010100100110 Source IP Address 140.117.11.253 10001100011101010000101111111101 Destination IP Address 00000000000000000000000000000000 Source Port Destination Port 0000000001000011 0000000001000100 UDP Length Checksum 0000000000110000 0000000000110111 Version: 表示 IP 封包的版本 IHL: 表示 IP 封包標頭的長度 DSCP: 優先級分類為三種EF、AF、BSF 從左到右由優先級高變低 ECN: 擁塞通知，11表示擁塞 Total Length: 封包的總長度，包括封包標頭及資料 的長度 Identification: 資料分割後使用的辨識碼 Flags: 格式為 ”0DM” D表示是否可分段，1表示不可 分段，M表示是否有更多分段，0表示最後資料 Fragment Offset: 這段資料在原始資料中所在的位址 Time to Live: 表示封包能經過的 Router 數量 Protocol: 表示該 IP 封包的後續協定 Header Checksum: 標頭檔的錯誤檢查碼 • • • • • • • • • • •
DHCP Reply 封包 DHCP header OP HTYPE HLEN HOPS 00000001 00000001 00000110 00100000 Transaction ID 00000000000000000000000011111111 Seconds Flags 0000000000000001 0000000000000001 Client IP Address(ciaddr) 00000000000000000000000000000000 You IP Address(yiaddr) 140.117.157.43 10001100011101011001110100101011 DHCP Server IP Address(siaddr) 140.117.11.253 10001100011101010000101111111101 Gateway IP Address(giaddr) 140.117.157.254 10001100011101011001110111111110 Client Hardware Address(chaddr) 11110000111100001111000011110000 Server Name(sname) 00001111000011110000111100001111 File Name 00000000000000000000000000000000
