Does Battle.net allow you to resume your current connection after a temporary disconnect?  If so, how long do they wait before they drop the connection?

I tried it out with this simple heartbeat system I implimented in my bot.  I unplugged my phone cord for about 10 seconds and then plugged it back in.  The bot remained stable and continued receiving/sending SID_PING's (after the connection came back up), but after a minute or two, Battle.net dropped me with a RST.  I also experienced other problems as soon as the connection resumed such as receiving a stream of about 5 or 6 SID_PING's in a row which I'm guessing were just the packets that were queued on the server's out buffer.

How would it know your connection was ever unplugged?  Assuming that neither your socket nor battle.net's was ever closed, it would just think the packets are being dropped and they'd be queued by the socket until the connection timed out.  The packets on both sides would get sent when the connection resumes, and neither would know the connection was ever broken (how would they?)

I would suspect that's what happened.

<edit> completely re-wrote.  Same idea, but I didn't like my old answer.

That depends on the ISP's configuration; it might return host unreachable messages which would cause the TCP connection to drop (if you discconnected from the ISP).