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OPS235 Lab 7

40 bytes added, 08:01, 28 June 2016
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'''Perform the following steps:'''
# Switch to your '''centos3''' VM.<br><br>'''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)<br><br>
# <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:<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></li># <li>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>
#::<span style="font-family:courier">RSA key fingerprint is 53:b4:ad:c8:51:17:99:4b:c9:08:ac:c1:b6:05:71:9b.</span><br>
#::<span style="font-family:courier">Are you sure you want to continue connecting (yes/no)? yes</span><br>
#::<span style="font-family:courier">Warning: Permanently added 'centos3' (RSA) to the list of known hosts.</span><br><br></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: <b><code><span style="color:#3366CC;font-size:1.2em;">hostname</span></code></b></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 <u>reinstalled</u>)]]
<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 <b><code><span style="color:#3366CC;font-size:1.2em;">exit</span></code></b>.
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