Reordering the three-way-handshake - [CNP3] Computer Networking : Principles, Protocols and Practice | INGInious

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Author(s)	Olivier Bonaventure
Deadline	No deadline
Submission limit	No limitation
Category tags	tcp

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Reordering the three-way-handshake

A TCP connection, as explained in the TCP chapter of Computer Networking: Principles, Protocols and Practice always starts with a three-way-handshake.

Paste this command into your terminal:

The password to connect is

Three-way handshake

Can you correctly reorder the three segments that are used to establish a TCP connection ?

#	Length	Summary	Status
0	20 bytes	`Transmission Control Protocol, Src Port: 53718, Dst Port: 1234, Seq: 4119273527, Ack: 20522820, Len: 0`
1	24 bytes	`Transmission Control Protocol, Src Port: 1234, Dst Port: 53718, Seq: 20522819, Ack: 4119273527, Len: 0`
2	24 bytes	`Transmission Control Protocol, Src Port: 53718, Dst Port: 1234, Seq: 4119273526, Len: 0`

0000 d1d604d2f5872037 0139274450107080
0010 00000000

0000 ÑÖ.Òõ. 7.9'DP.p.
0010 ....

Transmission Control Protocol, Src Port: 53718, Dst Port: 1234, Seq: 4119273527, Ack: 20522820, Len: 0
- Source Port: 53718
- Destination Port: 1234
- Sequence number: 4119273527
- Acknowledgment number: 20522820
- 0101 .... = Header Length: 20 bytes (5)
- Flags: 0x010 (ACK)
  - 000. .... .... = Reserved: Not set
  - ...0 .... .... = Nonce: Not set
  - .... 0... .... = Congestion Window Reduced (CWR): Not set
  - .... .0.. .... = ECN-Echo: Not set
  - .... ..0. .... = Urgent: Not set
  - .... ...1 .... = Acknowledgment: Set
  - .... .... 0... = Push: Not set
  - .... .... .0.. = Reset: Not set
  - .... .... ..0. = Syn: Not set
  - .... .... ...0 = Fin: Not set
- Window size value: 28800
- Urgent pointer: 0

0000 04d2d1d601392743 f587203760127080
0010 00000000020405a0

0000 .ÒÑÖ.9'Cõ. 7`.p.
0010 ........

Transmission Control Protocol, Src Port: 1234, Dst Port: 53718, Seq: 20522819, Ack: 4119273527, Len: 0
- Source Port: 1234
- Destination Port: 53718
- Sequence number: 20522819
- Acknowledgment number: 4119273527
- 0110 .... = Header Length: 24 bytes (6)
- Flags: 0x012 (SYN, ACK)
  - 000. .... .... = Reserved: Not set
  - ...0 .... .... = Nonce: Not set
  - .... 0... .... = Congestion Window Reduced (CWR): Not set
  - .... .0.. .... = ECN-Echo: Not set
  - .... ..0. .... = Urgent: Not set
  - .... ...1 .... = Acknowledgment: Set
  - .... .... 0... = Push: Not set
  - .... .... .0.. = Reset: Not set
  - .... .... ..1. = Syn: Set
  - .... .... ...0 = Fin: Not set
- Window size value: 28800
- Urgent pointer: 0
- Options: (4 bytes), Maximum segment size
  - TCP Option - Maximum segment size: 1440 bytes
    - Kind: Maximum Segment Size (2)
    - Length: 4
    - MSS Value: 1440

0000 d1d604d2f5872036 0000000060027080
0010 00000000020405a0

0000 ÑÖ.Òõ. 6....`.p.
0010 ........

Transmission Control Protocol, Src Port: 53718, Dst Port: 1234, Seq: 4119273526, Len: 0
- Source Port: 53718
- Destination Port: 1234
- Sequence number: 4119273526
- Acknowledgment number: 0
- 0110 .... = Header Length: 24 bytes (6)
- Flags: 0x002 (SYN)
  - 000. .... .... = Reserved: Not set
  - ...0 .... .... = Nonce: Not set
  - .... 0... .... = Congestion Window Reduced (CWR): Not set
  - .... .0.. .... = ECN-Echo: Not set
  - .... ..0. .... = Urgent: Not set
  - .... ...0 .... = Acknowledgment: Not set
  - .... .... 0... = Push: Not set
  - .... .... .0.. = Reset: Not set
  - .... .... ..1. = Syn: Set
  - .... .... ...0 = Fin: Not set
- Window size value: 28800
- Urgent pointer: 0
- Options: (4 bytes), Maximum segment size
  - TCP Option - Maximum segment size: 1440 bytes
    - Kind: Maximum Segment Size (2)
    - Length: 4
    - MSS Value: 1440