Next week I will sit for my CEH examen. I'm still struggling with converting IP adresses from decimal to normal expression of the IP-adress, for instance

the decimal IP = 340590649

converted to normal expression should give: 203.2.4.5

How is this been calculated with a normal calculator?
What's the scientific method for converting?

Thanks for feedback,

The address 340590649 340590949 is expressed in decimal (dotless long format), if you then convert that address to hex you should get: CB020405
Since the IP address consists of 4 octets each part of the address is represented as:

CB (203) 02 (2) 04 (4) 5 (5)

If you want to convert to the long decimal URL:
linux.org= 198.182.196.56
Convert to HEX: 198 (C6) 182 (B6)  196 (C4) 56 (38)
http://0xC6B6C438
Convert HEX to Decimal: C6B6C438 = 3333866552 (decimal, dotless address)
http://3333866552

*Note: this only works with some browsers like IE, and this won't work with Firefox. Your results may vary though.

HTH


*edit: modified dotless address

This is still by far the easiest way to do it. If you have a good scientific calculator it should support hexadecimal, which makes converting to hex and back again easy.

Knowing how to do hex arithmetic is a useful skill. If you're only covering 8-bit numbers you only need work with numbers in the rannge of 0x00-0xFF or 0-255 in decimal. Don't beat yourself up over it though, it does not come naturally to most and taking a minute doing a simple sum in your head can be time well spent.

Jim

With the help of Data_Raid and the advice from Awesec to google, it seems that I got the method to convert. But my outcome is not what I expect. I do not seem to discover where I got wrong. It's for sure in the stage of converting  decimal to hex!

So I will detail my outcome, maybe someone can review it and point me to my mistake:

decimal 340590649

340590649/16      21.286.915  rest  9 this is in hex    9
21286915/16        1.330.432   rest   3             hex    3
1330432/16          83.152        rest   0             hex   0
83152/16              5.197         rest   0            hex    0
5197/16                324           rest    13          hex    D
324/16                  20             rest   4            hex    4
20/16                    1              rest    4            hex    4
1/16                      0              rest    1            hex    1


so in hex this gives:   144D0039


but the correct answer is:  CB020405


Pls can someone review this and give me feedback!

Chapeau Ignatius,

Now I can be sure that my calculations were right.

The fault is within the question and it came from an official and recommended instance!!

Great you solve the "bug" completely!!

Thanks!!

Now doubt any more over here concerning converting IP adresses!!

Here's another tip.

The C|EH is multiple choice, so you don't necessarily have to be able to go both ways to pass the test. (I understand that this doesn't help you learn for the sake of learning) But, the easiest (for me at least) solution is to work from the IP address to hex to binary to decimal. So no matter which way they ask the question, since I have all the possible answers, I can get to the correct answer fairly quickly by a process of elimination if they ask me to go from decimal to IP.

HTH