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OPS235 Lab 7

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# Switch to your '''centos3''' VM.

# Run the '''netstat-atunp''' command (pipe to "grep ~~ssh~~sshd") 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: <code>ssh ops235@centos3</code> (Where 'ops235' is the account on centos3 and 'centos3' is the hostname of the centos3 VM.)

# You should receive a message similar to the following:

# Issue the following command to confirm that you connected to your centos3 VM: <code>hostname</code>

[[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 reinstalled)]]

<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 <code>exit</code>.<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: <code>hostname</code>

<li>Use the Internet to search for '''TCP 3 way handshake''' to see how TCP connections are established and closed. </li>

Msaul

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OPS235 Lab 7

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