#!/bin/bash
# All credits for this one liner go to the author of this blog:
# http://scytale.name/blog/2010/01/fritzbox-wan-ip
# As the author explains its not required to tamper with the provided IP for the FritzBox
# as it always binds to that address for UPnP.
# Disclaimer: It might be necessary to make the script executable

curl -s -H 'Content-Type: text/xml; charset="utf-8"' \
  -H 'SOAPAction: urn:schemas-upnp-org:service:WANIPConnection:1#GetExternalIPAddress' \
  --data-binary '<?xml version="1.0" encoding="utf-8"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:GetExternalIPAddress xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1" /></s:Body></s:Envelope>' \
  http://169.254.1.1:49000/upnp/control/WANCommonIFC1 | \
  sed -n -e 's#^.*<NewExternalIPAddress>\(.*\)</NewExternalIPAddress>.*$#\1#p'