Re: What IP address is this log entry coming from? (Is "::" a valid IP address?)

[Apache Issues <apacheissues@xxxxxxxxx>]

Oooookay...  That makes it rather difficult to track down a solution.  Any theory as to why this occurs/how this can occur would be quite helpful.

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From: Tom Evans <tevans.uk@xxxxxxxxxxxxxx>
To: users@xxxxxxxxxxxxxxxx
Sent: Wed, September 1, 2010 8:12:23 AM
Subject: Re: What IP address is this log entry coming from? (Is "::" a valid IP address?)

On Tue, Aug 31, 2010 at 12:00 AM, Apache Issues <apacheissues@xxxxxxxxx> wrote:
> I'm using:
>
> CustomLog "/var/log/apache2/access_log" "%a %l %u %t \"%r\" %>s %b
> \"%{Referer}i\""
>
> And I occasionally see this right around the time the CPU starts running at
> 100%:
>
> :: - - [27/Aug/2010:12:28:01 -0700] "GET /favicon.ico HTTP/1.1" 200 - "-"
>
> %a is supposed to be an IP address, so what IP address is "::"? I'm only
> somewhat familiar with IPv6 but I've never seen "::" before.

http://en.wikipedia.org/wiki/IPv6_address#Notation

One or any number of consecutive groups of zero value may be replaced
with two colons. [ ... ]

The localhost (loopback) address, 0:0:0:0:0:0:0:1, and the IPv6
unspecified address, 0:0:0:0:0:0:0:0, are reduced to ::1 and ::,
respectively.

Cheers

Tom