Re: Get the external IP address from a Linux box

[Miles Fidelman <mfidelman@meetinghouse.net>]

On 5/24/18 4:22 PM, Erwan David wrote:

> Le 05/24/18 à 22:17, Stefan Monnier a écrit :
> > Alberto Luaces <aluaces@udc.es> writes:
> >
> > > Joe writes:
> > >
> > > > On the assumption that you are using a router of some kind, your public
> > > > IP address will be that of the router WAN port (cable, ADSL, etc.) and
> > > > there will be a method of determining that by connecting to the router
> > > > as an administrator. That method will depend entirely on the router.
> > > If the router supports upnp and it is activated, you can check the
> > > external IP in an device-independent way with
> > >
> > > upnpc -l | grep ExternalIPAddress
> > The miniupnpc Debian package even comes with the `external-ip` script
> > which basically does the above.
> >
> > I just tried it and it worked (tho only after I installed & enabled
> > miniupnpd on my OpenWRT router).  Of course, the IP address that my
> > router gets could itself be an "internal IP" behind a NAT firewall of my
> > ISP, so even if `external-ip` does give an answer I'm not sure it's
> > guaranteed to be "the" external IP address.
> >
> >
> >          Stefan
> You could also be natted to one pool, so get different addresses for
> different connections, or even have different services natted to
> different pools (eg because there is a transparent proxy for outgoing
> HTTP connections)

On the assumption that you're connected to a NAT router - the easiest 
way is to log into the admin port on the router - usually there's a 
management interface that will tell you your external IP address.

Miles Fidelman

--
In theory, there is no difference between theory and practice.
In practice, there is.  .... Yogi Berra