Spamhunter's Resource

Octal Numbers

Allowable numbers in the Octal (base-8) system are: 0, 1, 2, 3, 4, 5, 6, and 7. The number 8 (base-10) would be represented as a "10" in octal since an "8" is not allowed. Similarly, the number 9 (base-10) would be shown as "11" in octal.

A value of 0203 would be a valid octal number since it starts with a leading zero (which implies octal) and consists of digits less than 8.

By way of contrast, hexadecimal (base-16) numbers start with a "#" in a web environment: #336699 would be used to specify a background color in hexadecimal. Some programming languages use "0x" before the value: 0x5ACE, for example.

Octal IP Number

Question and answer courtesy of John F. Sorenson and "Spamless", writing in news.admin.net-abuse.email.

The spamvertised site is at 00000000330.0000000012.19.00000000167. Can someone please translate this into something usefull me?

Numbers starting with "0" are treated the "normal" way C does it - they are octal.

The first  octet is then 330_octal=216_decimal
The second octet is then  12_octal= 10_decimal
The third  octet is                 19_decimal
The fourth octet is then 167_octal=119_decimal

So, writing as decimal octets (the way IP addresses are normally written) this is 216.10.19.119

Number base conversion on a scientific calculator
You can convert from Hexadecimal, decimal, octal, and binary using a scientific calculator.

Octal Number Contains "8" or "9"

Information courtesy of Norman DeForest.

One thing to watch out for are invalid "octal" numbers with the digits '8' or '9' in them. Some clueless browsers (Netscape and IE) don't reject such digits but, instead, multiply them by the [otherwise] appropriate power of eight so numbers like '039' are misinterpreted as "3*8 + 9 = 33" when the correct octal is "041".

That means that the browser will work with the URL but some net tools that properly reject invalid digits will not work. You have to work the conversion by hand or use a tool such as the URLomatic on the Sam Spade site (which deliberately accepts such munbers so that the address accessed by the buggy browsers can be identified). A pocket calculator (or the Windows Calculator) with binary/octal/decimal/hexadecimal conversions will not work in those cases.