Decimal IP address (thing)

Let's take the URL http://www.everything2.com/ by way of example.

Using whichever tool you like, determine the IP address of this site. You'll find that this maps to the address 206.170.14.131.

206.170.14.131 is stored internally by a computer in binary format. 206.170.14.131 converted to binary looks like this:

11001110 "." 10101010 "." 00001110 "." 10000011

(Note the padding of the third octet, "14", to eight digits by adding extra zeroes. By definition each octet must contain eight bits of information . The maximum number you can have represented with 8 bits of information in binary is 11111111 or 255 in decimal.)

Dotted quad notation is confusing. The dots simply separate the four octets but this tends to hide the fact that the address itself is stored as one value inside the computer, not four. You can also represent the same values in hexadecimal as:

CE "." AA "." 0E "." 83

(Note here also that "14" is again padded - this time to 2 digits - with a zero. Hexadecimal or base 16 needs only two digits to represent the maximum of 255 - FF)

Now let's drop the dots, since they're really confusing the issue a lot here. The proper way to represent the address 206.170.14.131 is:

11001110101010100000111010000011 (binary)
Or CEAA0E83 (Hexadecimal).

The binary version is the computer's internal representaion of that address. CEAA0E83 is also a handy way of storing the data.

Convert either of those to their decimal values, and you have the decimal IP address. Observe:

11001110101010100000111010000011₂
= CEAA0E83₁₆
= 3467251331₁₀

So, try typing http://3467251331/ into your browser, and see what happens!

(Disclaimer: Your browser may not support this type of addressing)