From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-01-27T07:53:05+09:00
Subject: Re: Getting the dynamic IP address of a dialup interface (ppp0)

On Mon, Jan 27, 2003 at 07:37:38AM +0900, Eric Hodel wrote:
> Mauricio Fern?ndez (batsman.geo@yahoo.com) wrote:
> 
> > 
> > I need to get the dynamic IP address of the ppp0 interface
> > (point-to-point) under Linux. I cannot do a reverse DNS
> > lookup since the associated name is dynamic too (something like
> > user-bla-bla-IP-.someisp.com), and I would prefer to avoid parsing
> > `/sbin/ifconfig` since
> >  a) I don't know how reliable it would be (and it's ugly anyway)
> >  b) I cannot get sample output to work on since I have no access to the
> > remote machine (I was planning on somebody installing my script that)
> > 
> > [Context: I'm binding a socket to that interface and sending the IP and
> > port info w/ UDP to another computer (server) behind a firewall that then
> > connects to the client. This is all required because of quite draconian
> > firewalling rules (my machine is behind _THREE_ different firewalls,
> > ouch!)]
> 
> ifconfig should be virtually the same everywhere, so parsing should be
> something like this: (works on FreeBSD)
> http://segment7.net/ruby-code/snippits/get_ip.rb

Great! I have been reading ifconfig's (net-tools's) sources, and
apparently that info is taken from /proc/net/ (under Linux at least) and
using ioctl, and I guess parsing is more portable than trying ioctl
magic... 

-- 
 _           _                             
| |__   __ _| |_ ___ _ __ ___   __ _ _ __  
| '_ \ / _` | __/ __| '_ ` _ \ / _` | '_ \ 
| |_) | (_| | |_\__ \ | | | | | (_| | | | |
|_.__/ \__,_|\__|___/_| |_| |_|\__,_|_| |_|
	Running Debian GNU/Linux Sid (unstable)
batsman dot geo at yahoo dot com

Computers are like air conditioners.  Both stop working, if you open windows.
	-- Adam Heath