IP header checksum calculation If an IP header is 0x45000030

IP header checksum calculation. If an IP header is 0x4500003044224000800600008c7c 19acae241 e2b. Calculate the checksum. Many business computers have three distinct and worldwide unique identifiers. What are they?

Solution

given IP header is

4500 0030 4422 4000 8006 0000 8C7C 19AC AE24 1E2B

NOw convert all these values into binary

4500 - 0100010100000000

0030 - 0000000000110000

4422 - 0100010000100010

4000 - 0100000000000000

8006 - 1000000000000110

0000 - 0000000000000000 // since the checksum is set to zero

8c7c - 1000110001111100

19ac - 0001100110101100

ae24 - 1010111000100100

1e2b - 0001111000100100

lets add all these binary nos one by one.

4500 - 0100010100000000

0030 - 0000000000110000

4530 - 0100010100110000 // first result

4530 - 0100010100110000 // first result plus next 16 bit word

4422 - 0100010000100010

8952 - 1000100101010010 // 2nd result

8952 - 1000100101010010 // 2nd result next 16 bit word

4000 - 0100000000000000

C952 - 1100100101010010 // 3RD result

C952 - 1100100101010010 // 3r result plus next 16 bit word

8006 - 1000000000000110

12958 - 10100100101011000 // 4th result here extra carry add the odd bit

2958 - 0100100101011001 // 4th result plus next 16 word

8c7c - 1000110001111100

d5d5 -1101010111010101 // 5th result

d5d5 - 1101010111010101 // 5th result plus next 16 word

19ac - 0001100110101100

ef81 - 1110111110000001 // 6th result

ef81 - 1110111110000001 // 6th result next 16 word

ae24 -1010111000100100

9ea5 -11001111010100101// 7th result extra carry

9ea6 -1001111010100110// 7th result

1e2b -0001111000100100

bcd1 -1011110011010001 // 8th result

this is the final result. atlast find 1\'s compliment to the result

The final result is 0100001100101110 - 432e.

2 Ans: IP address, Device serial number and Operating system serial number