Get the external IP address from a Linux box

[Erwan David <erwan@rail.eu.org>]

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)