Getting local IP address...

[stephen at cerebralmaelstrom.com.bbs]

    Um, jeez. I'm rather surprised by these responses -- I assumed it
was some simple little function somewhere I was missing.. I'm also
even more surprised at the differences between the three approaches

-- #1 -- socket.gethostbyname(socket.gethostname())
-- #2 -- Some complicated stuff dealing with asking Linux (which,
incidentely, is bad since i'm primarily on a Windows machine for
the time being -- and in the future will be on a *BSD, and hope
to have my program working on all three :)) what the address is
on the given ethernet card..
-- #3 -- Just go all out and connect, since in the process you
have to be telilng the other side where you are, so you can
get it that way.

#2 and #3 just seem .. convoluted .. as heck. But because so
many people sugguested them, I have to assume that they
beileve there is some central problem with #1... What is it? :)


David Bolen <db3l at fitlinxx.com> wrote in message
news:uitu45ihv.fsf at ctwd0143.fitlinxx.com...
> Mike Fletcher <mfletch at tpresence.com> writes:
>
> > import socket
> > def getLocalHostIP( remote = ("www.python.org", 80)):
> > '''Get the "public" address of the local machine, i.e.
> > that address which is connected to the general internet.
> > Code by Donn Cave, posted to comp.lang.python'''
> > s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
> > s.connect( remote )
> > ip, localport = s.getsockname()
> > s.close()
> > return ip
> >
> > That is actually from a Deja posting, seems to be fairly portable,
doesn't
> > rely on parsing obscure Unix command responses, is readable, and is
> > generally quite reliable.
>
> But has a pretty large (IMHO) negative that you are making a wasted
> network connection to an external server that has to spend time
> setting up and tearing down TCP with you for no reason.  That seems a
> pretty high overhead to pay just to determine what is essentially a
> locally configured piece of information.  If you are in charge of your
> own server that you are using I suppose that's one thing, but it seems
> a big waste if you're connecting to someone else's.
>
> Unfortunately, really determining a local configured address just
> isn't that portable a thing from my experience.  Probably the closest
> would be the SIOCGIFCONF IOCtl (for Unix systems) as previously
> posted.  There is an Windows socket IOCtl that is similar
> (SIO_ADDRESS_LIST_QUERY), but I'm not sure how best to get to it from
> Python, aside from something like a CallDLL approach.
>
> While without an alternative that is portable as the above example
> makes it hard to come out too strong against it, I did want to point
> out that while it may be portable and readable, it has negatives on
> the network side in terms of wasted connections.  I built backbones in
> a prior life, and I sort of cringe to think of tons of user code
> suddenly starting to do stuff like the above :-)
>
> --
> -- David
> --
> /-----------------------------------------------------------------------\
>  \               David Bolen            \   E-mail: db3l at fitlinxx.com  /
>   |             FitLinxx, Inc.            \  Phone: (203) 708-5192    |
>  /  860 Canal Street, Stamford, CT  06902   \  Fax: (203) 316-5150     \
> \-----------------------------------------------------------------------/




-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----==  Over 80,000 Newsgroups - 16 Different Servers! =-----