A Practical Guide to Red Hat® Linux® 8

Network Security

Network security is vital to the security of a computing site. However, without the right infrastructure, providing network security is difficult, if not impossible. For example, if you run a shared network topology,^[5] such as Ethernet, and have in public locations jacks that allow anyone to plug in to the network at will, how can you prevent someone from plugging in a machine and capturing all the packets (page 1483) that traverse the network?^[6] You cannot, so you have a potential security hole. Another common security hole is the use of telnet for logins. Because telnet sends and receives cleartext, anyone “listening in” on the line can easily capture login names and passwords, compromising security.

^[5] Shared network topology: ...