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OPS235 Lab 7

40 bytes added, 07:01, 28 June 2016

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'''Perform the following steps:'''

# Switch to your '''centos3''' VM. ~~'''NOTE:'''~~ 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)

# <ol><li value="2">Run the '''netstat -atunp''' command (pipe to "grep sshd") to check the state of a possible ''ssh connection''. What is the state (i.e. LISTENING or ESTABLISHED)?# <li>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.) </li># <li>You should receive a message similar to the following:

#::The authenticity of host 'centos3 (192.168.235.13)' can't be established.

#::RSA key fingerprint is 53:b4:ad:c8:51:17:99:4b:c9:08:ac:c1:b6:05:71:9b.

#::Are you sure you want to continue connecting (yes/no)? yes

#::Warning: Permanently added 'centos3' (RSA) to the list of known hosts. </li># <li>Answer '''yes''' to add to the list of known hosts.</li># <li>Issue the following command to confirm that you connected to your centos3 VM: <code>hostname</code></li></ol>

[[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 your '''centos3''' VM and re-run that same '''netstat pipeline command'''. Any change to the connection status?</li><li>Return to the second terminal, and log-out of your ssh connection by typing <code>exit</code>.

Msaul

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