TCP LISTEN can specify a mask for which machines a connection will be accepted from.
It sounds like your GF is only listening on 127.0.0.1:8080 rather than 0.0.0.0:8080 (which means all machines).
You can test that theory by doing netstat -an|grep LISTEN|grep 8080 (assuming you have these commands on your machine). It should say one of the above.
But, if that is the problem, I don't know how to fix it. There will be a configuration property somewhere in GF but I don't know where. I would suggest a trawl through the admin screens or hope that someone more knowledgeable replies.
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