are you successfully sending data to weather underground?
if so, then you must *sniff* traffic bound for port 80.
if not, then you must configure the access to send data to weather underground, configure dns spoofing so that the computer running weewx receives the http connections bound for wu, then *listen* for traffic on port 80.
to diagnose, run the interceptor driver directly, and use the --debug option if you need more info. (details are in the interceptor readme - or ask here if you're not sure)
you cannot do anything with encrypted traffic unless you figure out how to decrypt it. if you do that, please let us know - lots of people would like to know how to do that! it would be nice if we could decode the traffic to the acurite servers, since that contains all sensor data, not just the limited set of sensor data sent to wu.
m