Increasing the Robustness of UDP Applications
Because UDP is unreliable, problems arise when you least expect them. Although the echo client of Figure 18.5 looks simple, it actually contains a hidden bug. To bring out this bug, try pointing the client at an echo server running on a remote UNIX host somewhere on the Internet. Instead of typing directly into the client, redirect its standard input from a large text file, such as /usr/dict/words:
% udp_echo_cli1.pl wuarchive.wustl.edu echo </usr/dict/words
If the quality of your connection is excellent, you may see the entire contents of the file scroll by and the command-line prompt reappear after the last line is echoed. More likely, though, you will see the program get part way through the ...