Not sure how serious this is, but it looks like your bitcoind is listening on port 8333 (default) for incoming Bitcoin-esque connections. It's said that it's much easier to double spend when someone connects directly to your node and another at the same time.

On my DNS tunnel service, I have the daemon setup like this, to only connect out: bitcoind -noupnp -par=1 -daemon -nolisten. Granted, I'm not quite sure how relevant this for your environment. Not sure why you have portmapper open or port 41689, either.

Let me know what you think. Best of luck with the service!

Cheers,
Teran