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socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error

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  socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2011-12-22 06:40 -0800
    Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Rami Chowdhury <rami.chowdhury@gmail.com> - 2011-12-22 15:32 +0000
      Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2011-12-22 08:29 -0800
        Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error becky_lewis <bex.lewis@gmail.com> - 2011-12-23 02:41 -0800
          Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2011-12-23 09:14 -0800
            Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-02 05:25 -0800
              Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Heiko Wundram <modelnine@modelnine.org> - 2012-01-02 15:00 +0100
                Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-02 07:29 -0800
                  Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Roy Smith <roy@panix.com> - 2012-01-02 10:47 -0500
                    Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-02 10:17 -0800
    Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error becky_lewis <bex.lewis@gmail.com> - 2011-12-22 07:52 -0800
    Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-01-02 16:49 +0100
      Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-02 10:18 -0800
        Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Roy Smith <roy@panix.com> - 2012-01-02 13:42 -0500
          Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-02 11:51 -0800
            Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Roy Smith <roy@panix.com> - 2012-01-02 15:31 -0500
              Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-09 14:19 -0800
                Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Dominic Binks <dbinks@codeaurora.org> - 2012-01-09 14:35 -0800
                  Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-09 15:04 -0800
                  Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-01-10 07:42 +0100
                    Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Chris Angelico <rosuav@gmail.com> - 2012-01-10 18:29 +1100
                Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Chris Angelico <rosuav@gmail.com> - 2012-01-10 10:14 +1100
                Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Nick Dokos <nicholas.dokos@hp.com> - 2012-01-09 18:32 -0500
                Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Chris Angelico <rosuav@gmail.com> - 2012-01-10 13:08 +1100
          Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error Νικόλαος Κούρας <nikos.kouras@gmail.com> - 2012-01-02 11:54 -0800

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#18739

On Tue, Jan 10, 2012 at 5:42 PM, Thomas Rachel
<nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de>
wrote:
> BTW: This behaviour might be useful with gethostbyaddr() as well - if the
> first one returned has gone away, you have the chance to reach the 2nd
> one...

In its directest sense, probably not. All you're getting is multiple
names for the same IP address. But if some of those names resolve to
multiple IP addresses, then it's entirely possible that what you say
is so.

ChrisA

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#18715

On Tue, Jan 10, 2012 at 9:35 AM, Dominic Binks <dbinks@codeaurora.org> wrote:
> The address database can have multiple names for the same IP address so
> gethostbyaddr returns a list - [0] being the first item in the list (and
> usually considered the canonical name)

Point to note: The inverse operation, getting IP addresses from names,
quite frequently returns multiple results - and in that case, there's
no "canonical name". You'll still usually want to take the zeroth
(first) item in the list, but often the list will change in order.
Try, for instance:

$ dig +short www.google.com

which uses DNS rotation as a form of load-balancing.

In any case, you normally just take the first entry.

ChrisA

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#18719

Chris Angelico <rosuav@gmail.com> wrote:

> On Tue, Jan 10, 2012 at 9:35 AM, Dominic Binks <dbinks@codeaurora.org> wrote:
> > The address database can have multiple names for the same IP address so
> > gethostbyaddr returns a list - [0] being the first item in the list (and
> > usually considered the canonical name)
> 
> Point to note: The inverse operation, getting IP addresses from names,
> quite frequently returns multiple results - and in that case, there's
> no "canonical name". You'll still usually want to take the zeroth
> (first) item in the list, but often the list will change in order.
> Try, for instance:
> 
> $ dig +short www.google.com
> 
> which uses DNS rotation as a form of load-balancing.
> 
> In any case, you normally just take the first entry.
> 

On both 2.6.6 and 2.7.1, the doc says: 

,----
| >>> help(socket.gethostbyaddr)
| Help on built-in function gethostbyaddr in module _socket:
| 
| gethostbyaddr(...)
|     gethostbyaddr(host) -> (name, aliaslist, addresslist)
|     
|     Return the true host name, a list of aliases, and a list of IP addresses,
|     for a host.  The host argument is a string giving a host name or IP number.
`----

so socket.gethostbyaddr(os.environ['REMOTE_ADDR'])[0] is the 0th element
of the tuple, i.e. the *name* that is returned. So (unless I'm confused
which is always a distinct possibility) this has nothing to do with
load-balancing or multiple addresses: it's the equivalent of 

  dig +short -x <addr>

Nick

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#18728

On Tue, Jan 10, 2012 at 10:32 AM, Nick Dokos <nicholas.dokos@hp.com> wrote:
> Chris Angelico <rosuav@gmail.com> wrote:
>> Point to note: The inverse operation, getting IP addresses from names,
>
> so socket.gethostbyaddr(os.environ['REMOTE_ADDR'])[0] is the 0th element
> of the tuple, i.e. the *name* that is returned.

Correct, I was drawing a noteworthy parallel with the inverse - gethostbyname.

ChrisA

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#18346

On 2 Ιαν, 20:42, Roy Smith <r...@panix.com> wrote:
> In article
> <bacea15d-fae0-4b1f-8a8e-a8b06b561...@t30g2000vbx.googlegroups.com>,
>  ÉΪÉ«É»όλαος Κούρας <nikos.kou...@gmail.com> wrote:
>
> > I'am trying to present myself through my webpage as computer tech.
> > Is the background music so bad?! :-)
>
> Yes.  Background music on web sites is evil.

Evil?!?! How come? :)

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