Sana147
2 years ago
1 changed files with 51 additions and 6 deletions
@ -1,12 +1,57 @@ |
|||||
This folder contains detail for Test_Case2. |
This folder contains detail for Test_Case2. |
||||
|
|
||||
Source IP = 192.168.10.20, which is c0a8 0a14 in hex |
|
||||
Destination IP = 192.168.10.10, which is c0a8 0a0a in hex |
|
||||
Source Port = 2341, which is 0925 in hex, |
|
||||
Destination Port = 1200, which is 04B0 in hex. |
|
||||
|
|
||||
|
1. Verison = 4, to indicate IPv4 version is used. |
||||
|
2. IHL = 5, which indicates 20 bytes. |
||||
|
3. Type of Service = 0, |
||||
|
4. Total Length = 40, which is 28 in hex. The total windows size contains the total lenght of IP header plus data. |
||||
|
5. Identification = 0002, |
||||
|
6. Flags = All flags are set to zero, |
||||
|
7. Fragment Offset = For now, there is no fragment offset so, this value is set to 0. |
||||
|
8. TTL = 40s, which is 28 in hex. |
||||
|
9. Protocol = 6, which indicates TCP. |
||||
|
10. Header Checksum = initially zero and then changed to the 1's complement of the sum of 16 bit values of IP header + data. |
||||
|
11. Source IP = 192.168.10.20, which is c0a8 0a14 in hex |
||||
|
12. Destination IP = 192.168.10.10, which is c0a8 0a0a in hex |
||||
|
13. Source Port = 2341, which is 0925 in hex, |
||||
|
14. Destination Port = 1200, which is 04B0 in hex. |
||||
|
15. Sequence Number = 0 for now, |
||||
|
16. Acknowledgement Number = 0, |
||||
|
17. Flags: |
||||
For the SYN packet, the SYN Flag in the header has a value of 1. |
For the SYN packet, the SYN Flag in the header has a value of 1. |
||||
For the SYN+ACK packet, the SYN and ACK flags in the header have a value of 1. |
For the SYN+ACK packet, the SYN and ACK flags in the header have a value of 1. |
||||
For the ACK packet, the ACK flag in the header has a value of 1. |
For the ACK packet, the ACK flag in the header has a value of 1. |
||||
For the FIN packet, the FIN flag in the header has a value of 1. |
For the FIN packet, the FIN flag in the header has a value of 1. |
||||
For the FIN+ACK packet, the FIN and ACK flags in the header have a value of 1. |
|
||||
|
For the FIN+ACK packet, the FIN and ACK flags in the header have a value of 1. |
||||
|
18. TCP Checksum = initially zero, then: |
||||
|
(i) Concatenate TCP Pseudo header (Protocol, Source IP, Destination IP, Total Length) with TCP header and TCP data. This creates a big integer. |
||||
|
(ii) Convert this integer to binary and compute bit wise 1's complement. |
||||
|
19. Urgent Pointer = 0, no urgent data in the header. |
||||
|
|
||||
|
The value of header comes out to be: |
||||
|
header = {} |
||||
|
header[0] = 0x45, Version, IHL |
||||
|
header[1] = 0x00, TOS, |
||||
|
header[2] = 0x00, Total Length, |
||||
|
header[3] = 0x28, Total Length, |
||||
|
header[4] = 0x00, Identification, |
||||
|
header[5] = 0x02, Identification, |
||||
|
header[6] = 0x00, Flags + Fragment Offset, |
||||
|
header[7] = 0x00, Flags + Fragment Offset, |
||||
|
header[8] = 0x28, TTL |
||||
|
header[9] = 0x06, Protocol |
||||
|
header[10] = 0x00, Header Checksum |
||||
|
header[11] = 0x00, Header Checksum |
||||
|
header[12] = 0xc0, Source IP, |
||||
|
header[13] = 0xa8, Source IP, |
||||
|
header[14] = 0x0a, Source IP, |
||||
|
header[15] = 0x14, Source IP, |
||||
|
header[16] = 0xc0, Destination IP, |
||||
|
header[17] = 0xa8, Destination IP, |
||||
|
header[18] = 0x0a, Destination IP, |
||||
|
header[19] = 0x0a, Destination IP, |
||||
|
|
||||
|
The value of IP_Header_Checksum comes out to be: ed1c. |
||||
|
|
||||
|
References: |
||||
|
1. https://www.thegeekstuff.com/2012/05/ip-header-checksum/ |
||||
|
2. https://www.tutorialspoint.com/calculation-of-tcp-checksum |
Write
Preview
Loading…
Cancel
Save
Reference in new issue