for my problem i give a little example:

1. execute this:
exec 5<>/dev/tcp/www.google.com/80
(now we have a connection to google using descriptor 5)
2. create a shell script (google.sh)
#[begin]
echo -e "GET / HTTP/1.0\n" >&5
cat <&5 1>/dev/null
#[end]

the script sends a get request using descriptor 5 (e.g. to google)
and retrieves the result (since i don't need everything on stdout i redirect it to /dev/null)
3. execute the shell script

what i need is transparent logging
this means, everything which is sent or received (in this example using descriptor 5) should be logged to a file (or two files, ingoing, outgoing)
i thought about using tee to redirect 5 to stdin/stdout or something
but i have no idea how to do this

any suggestion would be great

thx@ll

First supposition: make a fifo (with mkfifo) and run tee with output to log and to fifo (with input from socket). Then read the fifo instead. Reverse on output (try to log input first, not to spare efforts twice if I'm wrong).