The overall design is not quite right. I cannot see the reason why Tk is involved here, at least base what you presented.

Now under this design, your program only accepts connections when fileevent is fired, which I believe is not what you want, as most likely the client comes any time it wishes. This shall really be a simple socket server side program without Tk.

When your program reaches that line accept socket connection, it just hangs until a client comes, this is not what should happen to a GUI application. This makes the person sitting before the computer really frustrated (at least when I was trying to play with your code).

Multi-threading might help you (one the other hand, most likely you would need multi-thread any way, or other similar technologies, for a socket server that expects multiple clients at a single given time), but still better reconsider whether Tk is needed.