I can connect to my server on port 8081 no problem: if I do nc -l 8081 on my server, and nc my.host.name 8081 on my local machine, I can send and receive everything perfectly. But if I do polymer serve on my server, doing nc my.host.name 8081 on my local exits immediately, while nc localhost 8081 works just fine and I can see my index.html served to me if I fake an HTTP request. nc my.host.name 8081 also fails on the server.
What am I doing wrong? Why is polymer serve only listening to internal requests?
So apparently polymer serve only responds to requests made to localhost by default. Apparently there's a difference between localhost:8081 and the port 8081 that the rest of the world sees.
You can do polymer serve -H [external ip], where you get that external ip from ifconfig where it says inet addr:. Alternatively, I seem to be able to do polymer serve -H `hostname` though I'm not 100% sure that's a general solution.