ip address?

[Peter Hansen]

Jason Orendorff wrote:
> 
> Emile van Sebille writes:
> > >>> import os
> > >>> ipaddr = [ i for i in os.popen('route print').readlines()
> >   if i.split()[0] == '0.0.0.0' ][0].split()[3]
> 
> ...where ordinary humans would write something awful like...
> 
> import os
> 
> def get_address():
>     f = os.popen('route print', 'r')
>     lines = f.readlines()
>     f.close()
> 
>     for line in lines:
>         fields = line.split()
>         if fields[0] == '0.0.0.0':
>             return fields[3]
>     raise Exception, 'no routes found'

This finds the interface for the first default gateway.

Although it's probably an error, multiple default
gateways might be configured (especially when people
have dial-up connections which are configured wrong,
or VPN adapters).  And when this happens, I believe
Windows takes the *last* of the default gateways listed.
(Or maybe it uses the cost metric to decide which to
use, although maybe they can be the same...)