Question on port forwarding

[Sean Aaron Lisse]

  Hey folks... I'm still working on that automount/nfs/ssh combination.

  When you use "-L port:host:hostport" to forward a port on the localhost
to a port on a remote host,

  A) What is the origin that the remote system sees for the packets?  Is
it "port" on localhost, or the source of the messages sent to "port"?

  B) How connected is this?  Can you send a UDP message to "port" and have
it work correctly as if you'd sent it to "host:hostport"?  What about
creating a TCP connection?  

  Thanks, 
       Sean Lisse