It's a "blind" TCP proxy. It listens on one port, talks to another port. You can configure it to do load balancing (distribute connections among servers) or failover (switch from one server to another when one goes down). You can limit connections by IP address, track connections so a given IP will always connect to the same server, and so on.
What's new in this version:
fixes a problem where a remote host closed a connection too quickly, and getpeername failed. Plugdaemon was treating this as something that could only happen after the child was forked, and was aborting, instead of logging the error and closing the socket.
Operating System Support: Mac OS X 10.5 PPC, Mac OS X 10.5 Intel