Q:

How do I know if a NAT device is taking place on my network?

I am trying to deploy a Tahoe-LAFS grid on my machine, but other machines can't connect to mine. In the configuration doc it mentioned that a NAT device in action may need further configuration. So I am wondering that if my machine is connecting to a NAT device or not, how do I check it?

A:

You don't specify what "other machines" means. NAT takes place at a gateway or router. If the other machines are on another network, connected by one or more routers than it's possible you're having NAT issues. If they're on the same network, then NAT is not a potential issue.
To start diagnosing your issue, your should try pinging one of the remote machines, and having it ping your machine. If it works in both directions then NAT and associated routing issues are not the culprit (it's likely a firewall issue at that point, possibly on your local machine).

