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# Use your '''centos2''' VM to complete this section.
# Establish Open a terminal and run the '''netstat''' command (pipe to "grep sshd") to check the state of the connection. What is the state (i.e. LISTENING or ESTABLISHED)?# Open another terminal and establish an ssh connection to your '''centos3 ''' VM using the command:<br /><b><code><span style="color:#3366CC;font-size:1.2em;">ssh ops235@centos3</span></code></b><br>(Where 'ops235' is the account on centos3 and 'centos3' is the hostname of the centos3 VM.)<br><br>
# You should receive a message similar to the following:<br><br>
#::<span style="font-family:courier">The authenticity of host 'centos3 (192.168.235.13)' can't be established.</span><br>
# Issue the following command to confirm that you connected to your centos3 VM: <b><code><span style="color:#3366CC;font-size:1.2em;">hostname</span></code></b>
[[Image:spoof.png|thumb|right|485px|If you receive a message like the one displayed above, you should investigate why it is happening as it could indicate a '''serious security issue''', or it could just mean that something on '''the host has changed'''(i.e. the OS was <u>reinstalled</u>)]]
<ol><li value="6">Logout Switch back to the original terminal and re-run the netstat pipeline command again. Any change to the connection status?</li><li>Return to the second terminal, and logout of your ssh connection by typing <b><code><span style="color:#3366CC;font-size:1.2em;">exit</span></code></b>.<li>Run the netstat command in another the original terminal and check the state of the connection after logging out. Wait a few minutes and then check again. Record your observations.</li>
<li>Make certain to exit all connections, and that your shell is located in your <u>centos3</u> server. You can verify this by entering the command: <b><code><span style="color:#3366CC;font-size:1.2em;">hostname</span></code></b>
<li>Use the Internet to search for "TCP 3 way handshake" to see how TCP connections are established and closed.<br><br></li>
