Question

I was wondering how to manually convert an IP address to a hex value on an x86 machine. For example, the book I was reading gives the hex representation of 192.168.42.72 as:

    0x482aa8c0

but never explains how the conversion works. So, how does it?

Answer 1

When you convert an IP to a long integer, you take each octet in reverse order and multiply it by 256^n where n is the zero-based reverse index of the octet

So for this ip you’re doing

(72 * 256^0) + (42 * 256^1) + (168 * 256^2) + (192 * 256^3)
= 3232246344
= 0xc0a82a48

It looks like the book is doing it backwards, but you get the idea.