You are looking at a very old, but free version of the course.
If you are interesed the most recent version, check it out
on the Perl Maven site.
There are many other optiong to build a network server.
Besides providing more complex interaction with the single server one can
configure it to be able to handle multiple clients at the same time.
Just replace "use base 'Net::Server';"
by "use base 'Net::Server::PreFork';" and you have a preforking
If you are interested in on-site trainings by the author, please
contact me directly.