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== Purpose of Lab 7 ==
[[Image:shield.png|thumb|right|180px|Protecting a computer network from unauthorized access is one of the many day-to-day operations for a Linux system administrator and/or security specialist]]
Setting up a computer network is very important, but there are many other operations that occur on a daily basis that can include '''trouble-shooting''', '''repairing network connection issues''' as well as '''maintaining network security'''. System administrators need to '''protect or "harden" their computer networks from "penetration" from unauthorized computer users'''. Hardening a computer system can range from running an '''IDS''' (Intrusion Detection System) to monitoring and flagging suspicious activity to implementing screen savers on workstations.
In this lab, you will learn how to use '''ssh''', '''scp''', '''sftp''' commands to securely access and share data between authorized personnel. In addition, you will learn various methods of running and configuring an ssh server which include: using '''Public Key Authentication''', setting up an '''SSH tunnel''' in order to securely run graphical applications safely among computers in the network, '''disabling root login''', and '''changing the default ssh communication port''' to mislead potential penetration testers (also known as "pen-testers" or "hackers").
<u>Main Objectives</u>
* To set up, configure Secure Shell Services ('''ssh/sshd''')
* To use the '''ssh''', '''scp''', and '''sftp''' clients to access, copy, or transfer data among Linux servers in a secure manner
* Use ssh to '''tunnel X applications'''
* To tunnel network traffic via other communication ports
* To customize '''sshd''' to create a more private, secure system
==INVESTIGATION 1:==
<u>'''CONFIGURING AND ESTABLISHING AN SSH CONNECTION'''</u>
So far, you have learned to use the ssh utility to establish a secure connection to a remote server to perform tasks, administer the server, etc. For these common operations, you have issued the ssh command, which is the client application for ssh. In order to connect to a remote server (like your VMs, Matrix, etc) they need to be running the SSH service. In this lab, you will learn how to run an SSH server in a VM, then confirm that you can connect into the server by using the ssh client application.
We can use the '''netstat''' utility as a trouble-shooting / confirmation tool to view the SSH service and determine which STATE the SSH service is performing:
*'''LISTENING''' (waiting for a ssh connection attempt)
*'''ESTABLISHED''' (connection established)
*'''CLOSED''' (connection is closed)
*'''WAITING''' (time between connection closed, and changing to LISTENING mode)
<u>'''CONFIGURING AND ESTABLISHING AN SSH CONNECTION'''</u>
