The timeout command in rpcclient doesn't work. A timeout is only set if you executed the command. But if want to run a command which times out the connection isn't working:

Reproducer:
for i in $(seq -w 0 1200); do lpadmin -p "smb_printer$i" -E -v /dev/null; done

rpcclient //localhost -c 'timeout 90000;enumprinters'

Patch follows ...