Anonymous Monk has said that readline (i.e. my $response = <$socket>) blocks. This basically means that if the server is not ending its message with a newline, then readline will sit waiting for it. You can get around this by either 1) editing the server code so that it sends newlines or 2) using recv, which will allow you to specify how much you want to read.

What server are you connecting to? If you have the code, posting the relevant parts would be a great help.

Also, I hate to sound like a broken record, but Suffering from Buffering is a very good read.