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OPS235 Lab 7

27 bytes added, 17:24, 22 June 2016
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# Switch to your '''centos3''' VM.
# Run the '''netstat-atunp''' command (pipe to "grep sshsshd") to check the state of a possible ''ssh 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>
# 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="7">Switch back to the original terminal your '''centos3''' VM and re-run the that same '''netstat pipeline command again'''. Any change to the connection status?</li><li>Return to the second terminal, and logout log-out of your ssh connection by typing <b><code><span style="color:#3366CC;font-size:1.2em;">exit</span></code></b>.<li>Run the that same '''netstat ''' command in 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 remain in your '''centos2''' VM. When using ssh to connect to other servers, it is very easy to forget which server you are currently using. Verify that you are in your '''centos2''' VM 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>
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