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

References	(3 earlier) <roy-F4BA5C.13424802012012@news.panix.com> <24123dfe-b2fc-4f4c-8dfe-23bfef19b205@m10g2000vbc.googlegroups.com> <roy-4CE54B.15314102012012@news.panix.com> <f683b8f4-3a59-4c9f-94ef-82a9017dcd31@m20g2000vbf.googlegroups.com> <4F0B6BBE.5090501@codeaurora.org>
Date	2012-01-10 10:14 +1100
Subject	Re: socket.gethostbyaddr( os.environ['REMOTE_ADDR'] error
From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.4554.1326150869.27778.python-list@python.org> (permalink)

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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

Thread

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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