Calculating A Dotless IP Address

URLs are alphanumeric representations of IP octects, and all URLs that are based on a domain also have a corresponding IP address. For example, digitalpages.com is assigned to IP 209.68.14.46, and may be reached at address http://209.68.14.46/

To determine the Dotless IP address of a website, you must first know the IP address of the domain. You can determine that by asking your website hosting service or looking up your IP address in the handy-dandy IP lookup tool: http://dgl.com/ip.html

Once you've got the IP address of the website, you can calculate the Dotless IP address. Assume the IP URL is in the form of "http://aaa.bbb.ccc.ddd/"

The Dotless IP address, also called the "decimal address" can be calculated with this formula: decimal=aaa*16777216+bbb*65536+ccc*256+ddd

Multiplication Before Addition
Remember the standard order of mathematical operations: multiplication is evaluated before addition, so the equation could also be written: decimal=(aaa*16777216)+(bbb*65536)+(ccc*256)+ddd

For those of us who are math-challenged, here's an example. To find the Dotless IP address for address http://209.100.136.227:

1. Multiply the following equations:
1a. 209 * 16777216
1b. 68 * 65536
1c. 14 * 256

2. Then sum the equations of steps 1a-1c, and add 227

3506438144 + 4456448 + 3584 + 46 = 3510898222

3. The Dotless IP address of digitalpages.com, which is IP 209.68.14.46, is http://3510898222/

(paraphrased from http://www.itrain.org/itinfo/1999/it990304.html, check it out for potential IE security problems with Dotless IP's)

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