I cannot see where you set up $ui. Presumably it is with $IO::Socket::INET->new(). At any rate, I'd try a print of the inet_ntoa($remote_host) just after the my just in case your debuggery is incorrect. I say that because the close appears to be after the if and inside, not after, the while.

Update: You might want to send the client a message before the close, too. Also, $client->autoflush(1); is probably a good idea, too.

HTH, --traveler