■ IntroduCtIon
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• example.com and its associated machines represent the configuration of a simple
service-oriented machine room. Here, no network translation or masquerading is taking
place. The three servers behind example.com have service ports that are fully exposed to client
traffic from the Internet.• Each of the service machines ftp, mail, and www has correctly configured daemons up and
running so that Python scripts from this book can be run on the other machines in the
playground to connect successfully to representative examples of each service.• All of the service machines have correctly installed TLS certificates (see Chapter 6), and the
client machines all have the example.com signing certificate installed as a trusted certificate.
This means Python scripts demanding true TLS authentication will be able to achieve it.The network playground will continue to be maintained as both Python and Docker continue to evolve.
Instructions will be maintained in the repository for how to download and run the network locally on your own
machine, and they will be tweaked based on user reports to make sure that a virtual machine, which offers the
playground, can be run by readers on Linux, Mac OS X, and Windows machines.
With the ability to connect and run commands within any of the playground machines, you will be able to set
up packet tracing at whichever point on the network you want to see traffic passing between clients and servers. The
example code demonstrated in its documentation, combined with the examples and instruction in this book, should
help you reach a solid and vivid understanding of how networks help clients and servers communicate.