Recently ended up with one of these used. I did the full factory reset via CLI and enabled the GUI interface and also the FTP server to upload the current firmware. Only my laptop is connected to it via ethernet. The GUI interface is extremely slow and times out. When it does load most of the images and buttons do not load. So I tried to access via FTP to install the current firmware and while my FTP client does connect to it, I never get a username request and eventually a connection time out.
Maybe it's just shot and I should toss it?
I would attempt to upgrade the firmware either from the GUI or via TFTP before writing it off. Note that there are three hardware generations of the Netvanta 1234. Check the full part number of your device to be sure you are uploading the correct firmware for your hardware.
Also double check the port configurations and verify the port your laptop is plugged into is set to auto negotiate. If you are getting a duplex mismatch between the lap top and the switch port that can cause you are describing.