If you expect more than just a few hundred concurrent users, you may need to tune the server OS to increase the number of connections allowed.
RealChat server requires one file descriptor per concurrent user. UNIX/Linux operating systems limit the
number of file descriptors that a process may open. The limit varies across OSes (for Linux it is usually 1024). To
display the current value, or set the limit for the current session, use the ulimit -n command. To
permanently set the limit, consult your OS manual.