John's Tech Blog

Never quite learned the nitty gritty of IP addresses or subnet masks? Read this, and with any luck, it'll all click. (No pun intended.)

Number Theory, (Sun, Jul 2nd): "Yesterday we posted a diary entry about mystery URLs found in some Apache logs. We received many responses, and several readers pointed out that the strings are probably obfuscations of dotted-quad IP addresses. A few readers suggested that since the strings are nine numbers they could be US Social Security Numbers (for those outside the USA, we keep track of all our citizens through a system that is "not" supposed to be a national identity but has become one out of convenience; the nine-digit number is represented as XXX-YY-ZZZZ and the XXX part is a reference code to the general part of the USA you were in when you registered for the number.) I'll give you my theory about the mystery URLs in a moment.
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[Read the full story for a great lesson!]

From: SANS ISC