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{{Admon/caution|THIS IS AN OLD VERSION OF THE LAB|'''This is an archived version. Do not use this in your OPS235 course.'''}}= Configuring a Network Using Virtual Machines LAB PREPARATION=
==OverviewPurpose / Objectives of Lab 6==[[Image:network.png|thumb|right|150px|Setting up networks is an essential operation for a system administrator. Maintaining network connectivity and securing the network are also essential operations for a system administrator.]]
|}
=INVESTIGATION 1: CONFIGURING A VIRTUAL PRIVATE NETWORK=
For the remainder of this course, we will focus on networking involving our VMs and our c7host machine. This lab will focus on setting up a virtual private network ('''VPN'''), connecting our VMs and c7host machine to the VPN, and configuring our VPN to make more convenient to use, troubleshoot and protect. '''Lab 7''' will focus more on configuring SSH and making access to the VPN more secure. Finally, '''lab 8''' will focus on configuring the network for fixed workstations, mobile devices, or both at the same time.
==Part 1: Configuring a Private Network (Via Virtual Machine Manager) == [[Image:network-config-centos.png|thumb|600px|right|This diagram shows the current network configuration of your '''c7host''' machine in relation to your '''Virtual Machines'''. In this section, you will be learning to change the default network settings for both your '''c7host''' machine and '''VMs''' to belong to a '''virtual network''' using fixed IP Addresses. ]]If we are going to setup a private network, we must do 2 major operations: First, '''define a new private network in the Virtual Manager application'''; and second, '''configure each of our VMs to connect to this new private network'''. In Part 1, we will be perform the first operation. In parts 2, 3, and 4, we will be performing the second operation for all VMS (graphical and command-line). # Perform this section in your '''c7host''' machine.<br><br>'''NOTE:''' Before configuring our network we want to '''turn off dynamic network configuration for our Virtual Machines ''' by turning off the '''"default" ''' virtual network. We will then define our virtual private network. Follow the steps in order to perform these operations. <br><br># Perform this section in your Make certain that <u>'''c7hostALL''' machine.# Turn off your </u> virtual machines# Start Virtual Machine Managerare powered off.
# In the Virtual Machine Manager dialog box, Select '''Edit'''-> '''Connection Details'''.
# In the '''Hostsc7host Connection Details''' Details dialog box, select the '''Virtual Networks''' tab# Disable the default configuration from starting at boot by '''<u>deselecting</u>''' '''"Autostart"''' (on boot) checkbox''' check-box and click the '''Apply''' button.# Then Stop the default network configuration by clicking on the '''stop''' button at the bottom left-side of the dialog box.
# Click the '''add''' button (the button resembles a "plus sign") to add a new network configuration.
# Give your new network a name (i.e. '''network1''')then click the '''Forward''' button.# Enter In the next screen, enter in the new network IP address space:#*:'''192.168.235.0/24'''# Disable DHCP DHCP4 by '''deselecting''' the check boxand click the '''Forward''' button twice (accepting the defaults).# Enable Network Forwarding by Selecting '''Forwarding to physical network'''# The , the destination should be '''Any physical device''' and the mode should be '''NAT'''# Proceed with changes, and select click '''Finish'''.{{Admon/note | Repeat these steps for each VM | Complete the following steps on <u>each</u> of your virtual machines.}}
<ol>
<li value="1513">Now we need to We will now reconfigure each of our 3 VMs to use our new virtual network '''network1'''<ol type="a" style="margin-left:2cm"> <li value="1">Select the Let's start with our '''centos1 VM'''. Double-click on your '''centos1''' VM , but instead of running the VM, click on the '''view''' menu, and edit the select: '''Virtual Machine Details'''<br />(Note: the Virtual Machine window will appear - do not start virtual machine)</li> <li>Under View select '''Details'''</li>
<li>In the '''left pane''' of the Virtual Machine window, select '''NIC:''' and note that this NIC is on the "default" virtual network</li>
<li>Change it to '''Virtual Network network1: NAT''' (i.e. the VPN that you just created) and click the '''Apply' : NAT'' button.</li>
</ol>
</li>
<li>Repeat the same steps for your '''<u>centos2</u>''' and '''<u>centos3</u>''' VMs!</li>
</li>
</ol>
'''Answer the Investigation Part 1 observations / questions in your lab log book.''' == Part 2: Configuring VM Network Setup Graphically ('''system-config-network''')== For Parts 2 and 3 of this investigation, we will be using a graphical tool to connect our '''centos1''' and '''centos2''' VMs to our private network.
# In the '''IPv4 Settings''' tab change the method from "Automatic (DHCP)" to '''"Manual"'''.
# In the '''Addresses section''', click '''"Add"'''.# Manually set enter the IP configuration tofollowing information:#: IP Address : '''192.168.235.1211'''#: Subnet Mask : '''255.255.255.0'''#: Default Gateway : The IP address of <code>'''virbr1</code> ''' on your centos host.# Click on the '''DNS''' field and add The IP address of <code>(''virbr1</code> ''' on your centos host. ) as the primary DNS server.# Your network connection may take a couple of minutes to reconfigure connect (view When finished, check your settings, and then click the Network Manager applet in the gnome panel at the top of the screen)'''Apply''' button.# You should be able Open a terminal and issue the '''ifconfig''' command to use confirm the service commands to restart your networkIP ADDRESS settings change.#*<code>service network stop</code>#*<code>service network start</code># Verify your new interface that '''centos1'''VM is now connected to the VPN by examining issuing the output of following command from your '''c7host''' machine:<codebr>ifconfig</codeb># To verify that centos2 has the correct default gateway configured, use the commands <code>route <span style="color:#3366CC;font-n</codesize:1.2em;">, <code>ifconfigping 192.168.235.11</code>, <codespan>nslookup</code>, and <code>ping</codeb>
'''Answer the Investigation Part 2 observations / questions in your lab log book.'''
=== Investigation Part 3: What files does the <code>system-config-network</code> GUI tool change?. =Backing up Only Recent File Changes =={{Admon/note | Use centos1 | Complete this investigation on your centos1 VM.}}
{| width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/note | Backing up Files |One very important aspect of system admin is performing backups. There are many methods for backing up the data on a a computer system. The following is an example of a common backup system used in Business Unix/Linux systems:<br /><br />'''Full Backup''': Backup all specified files (eg. configuration, data files, etc)<br>'''Incremental Backup''': Backup of only files that have changed since last (full) backup.|}}|} # Keep your '''centos1''' VM running (you will need it running later in this lab).# Start the '''centos1centos2''' VM and login# Before we configure centos1 centos2 network configuration, we should create a timestamp file that can be used to see which files have changed as a result of using the GUI tool.Issue the following command:#* : <b><code><span style="color:#3366CC;font-size:1.2em;">date > /tmp/timestamp</span></code></b># Run the network configuration tool and enter the following static configuration in the same way that you configured '''centos2centos1'''.#* IP Address: '''192.168.235.1112'''
#* Subnetmask: '''255.255.255.0'''
#* Default Gateway: '''192.168.235.1'''
# Save and exit the network configuration tool.
# You may have to restart the network using the correct command.
# Verify the configuration by pinging centos host ('''192the VMs and c7host using their IP addresses.168.235.1# We will now create an ''') and centos2 (Incremental Backup'''192.168.235.12''') {{Admon/note | Creating an Incremental Backup |We will now be using Run the <code>find</code> following Linux command toas root:#:*Locate the configuration files (contained in the <codeb>/etc</code> directory) that were modified by the GUI network configuration program<span style="color:#3366CC;font-size:*Copy those configuration files to a "specified1.2em;" directory for backup purposes Previously, you created a file called <code>find /etc -newer /tmp/timestamp> /root/netcfg.lst</span></code> that just contains </b>#View the current date and time prior to running the network configuration toool for centos1'''/root/netcfg. Any files that were modified by the GUI network configuration program should have a timestamp later (or newer) than the "timestamp" lst''' file you created. All the Linux TCPWhat does it contain?</IP configuration files are stored under the li>#Create a new directory called: '''/etctmp/lab6''' directory or its sub{| width="40%" align="right" cellpadding="10"|-directories. The <code>find<valign="top"|{{Admon/code> command (tip | Tip | You can create a Bash Shell script file using the correct options) can be used to only list those files that have been recently created since ''find'' command above, give the timestamp date contained in shell script executable permissions, and use the <code>/tmp/timestamp</code> file''crontab'' command to schedule running this script on a periodic basis.|}}|}
<ol>
<li value="811">Run Issue the following Linux commandcommands: <uldl> <lidd><b><code><span style="color:#3366CC;font-size:1.2em;">find /etc -newer /tmp/timestamp >-exec cp {} /tmp/lab6 \; </root/netcfg.lstspan></code></lib> </uldl>
</li>
</ol>
'''Answer the Investigation Part 3 observations / questions in your lab log book.''' == Part 4: Configuring VM Network Setup via Command Line ('''centos3''') == Our centos3 VM is a '''text-based only''' system, thus we cannot use a graphical tool to configure centos3 to connect to our private network. Therefore we will learn how to perform this task by using command-line tools.
# To configure your card with a static address use the following command:
#* :<b><code><span style="color:#3366CC;font-size:1.2em;">ifconfig eth0 192.168.235.13 netmask 255.255.255.0</span></code></b>
# To configure a default gateway for that interface enter the command:
#* : <b><code><span style="color:#3366CC;font-size:1.2em;">route add default gw 192.168.235.1</span></code></b># To configure your a DNS server for this VM, edit the file <code>'''/etc/resolv.conf</code>'''. Change the <code>nameserver</code> line to beread:#* : <codeb>nameserver 192.168.235.1</codeb># Save your editing session.# Confirm your settings work by doing the following(you might need to do the steps '''3''' and '''4''' a few times before it works; keep checking with the commands below and wait a bit before each attempt):#* : <b><code><span style="color:#3366CC;font-size:1.2em;">ifconfig</span></code></b>#* :<b><code><span style="color:#3366CC;font-size:1.2em;">route -n</span></code></b>#* : <b><code><span style="color:#3366CC;font-size:1.2em;">ping</span></code> </b> (your other VM's and centos host.c7host)#* : <b><code><span style="color:#3366CC;font-size:1.2em;">ssh</span></code> </b> ( to your matrix Seneca's Matrix account to test your DNS)
# Restart the <code>centos3</code> VM, or just wait a few minutes.
# Login and test your configuration again. What happened?
# While we can configure network settings from the command line those settings are not persistent. To configure persistent network configurations we need to edit the configuration files:. # Change to the <code>'''/etc/sysconfig/network-scripts</code> ''' directory on <code></codebr>[[Image:new-network-config.png|thumb|300px|right|This diagram should show the newer network configuration of your '''c7host''' machine in relation to your '''Virtual Machines'''.]]#* List the contents of the this directory and you . You should see 2 different types of files, network config scripts and network configuration files.#* Look for the config configuration file for your original interface, it should be named <code>'''ifcfg-eth0</code>#* Make a backup of this file for later reference.'''#* Edit the new file for you interface and give it the following settings (or create a brand new file, might be easier than editing the old one):#**::DEVICE="eth0"#**::IPADDR="192.168.235.13"#**::NETMASK="255.255.255.0"#**::GATEWAY="192.168.235.1"#**::HWADDR="52:54:00:3f:5c:fa" <-- '''use the DO NOT COPY THIS VALUE! Use MAC address for YOUR interfaceusing:''' <code><span style="color:#3366CC;font-size:1.2em;">ifconfig eth0</span></code> #**::DNS1="192.168.235.1" '''#**::BOOTPROTO="static"#**::ONBOOT="yes"#**::NM_CONTROLLED="yes"#**::IPV6INIT="no"# Save the file and then restart the network connection by issuing the commands: <b><code><span style="color:#3366CC;font-size:1.2em;">ifdown eth1eth0</span></code></b> and then <b><code><span style="color:#3366CC;font-size:1.2em;">ifup eth1eth0</span></code></b>
# Verify your configuration as you did before.
# Restart the <code>'''centos3</code> ''' VM.# Login and attempt to <code>'''ssh</code> ''' to your matrix account to verify the settings.
'''Answer the Investigation Part 4 observations / questions in your lab log book.'''
=== Investigation 5INVESTIGATION 2: How do I setup local hostname resolution? ==VIRTUAL NETWORKING ENVIRONMENT TWEAKS AND OTHER USEFUL UTILITIES={{Admon/note | Use each machine | Complete this investigation on all of your VM's and the centos host.}}
== Part 1: Using Local Hostname Resolution =={|classwidth="collapsible40%" stylealign="background: #c0c0c0right" widthcellpadding="50%10"!Sample /etc/hosts file|-valign="top"|<pre># hostname centos1 added to {{Admon/etc/hosts by anaconda127note | Hosts files vs.0.0.1 localhost.localdomain localhost centos1the Domain Name System | On large public networks like the Internet or even large private networks we use a network service called [http::1 localhost6//en.localdomain6 localhost6 centos1 192wikipedia.168org/wiki/Domain_Name_System Domain Name System (DNS)] to resolve the human friendly hostnames like '''centos.235org''' to the numeric addresses used by the IP protocol.1 c6host192.168.235.11 centos1192.168.235.12 centos2192.168.235.13 centos3On smaller networks we can use the <code>/etc/hosts</precode>on each system to resolve names to addresses.}}
|}
After setting up a private network, it can be hard to try to remember IP addresses. In this section, we will setup your network to associate easy-to-remember server names with IP ADDRESSES.
# Complete this investigation on '''all of your VMs''' and the '''c7host''' machine.# Use the <b><code><span style="color:#3366CC;font-size:1.2em;">hostname</span></code></b> and <olb><code> <li valuespan style="color:#3366CC;font-size:1.2em;">ifconfig</span></code></b> commands on your c7host machine and all of your 3"VM's to gather the information needed to configure the '''/etc/hosts''' file on all of your Linux systems.# Edit the '''/etc/hosts''' file on <u>each</u> of the '''virtual machines and host machine'''. Add the following contents to the <u>bottom</u> of the '''/etc/hosts''' file:<br><br>#::192.168.235.1 c7host#::192.168.235.11 centos1#::192.168.235.12 centos2#::192.168.235.13 centos3<br><br>#Confirm that each host can ping all three of the other hosts by name.</li></ol>
'''Answer the Investigation 5 Part 1 observations / questions in your lab log book.'''
== Part 2: Obtaining MAC Address / Service Port / Firewall Information == === Investigation 6: How do I collect the MAC (Hardware) addresses of computers on my network? =Network Computers =={{Admon/note | Use your CentOS Host width="40%" align="right" cellpadding="10"| Complete this investigation on your CentOS host.}}- valign="top"|{{Admon/note | Obtaining Remote MAC Addresses| The term '''MAC''' address stands for '''Media Access Control''' address, which provides a unique ID to prevent confusion among computer systems within a network. While we use '''32bit IP addresse'''s to communicate over an internet, on the local ethernet network packets are delivered to a '''48bit hardware address''' (sometimes called a MAC address). The '''ARP''' protocol resolves 32bit IP addresses to 48bit MAC addresses by using a broadcast and caching the results. We can examine the ARP cache to get the MAC addresses of other computers on our local network.<br /><br />Being able to determine remote solve problems involving MAC address information is useful from troubleshooting networking programs to using addresses (such as '''WOLWake Up on Lan''' (Wake up on Lan) to automatically boot remote workstations via the network. In this investigation, you will learn how to obtain MAC address information for various network cards.}} # On the centos host <code>ping</code> each of your VM's# Examine the contents of the ARP cache by using the command <code>arp</code># Check the contents of the cache again by using the command <code>arp -n</code># What was the difference in output? For what other command did -n have a similar effect? '''Answer the Investigation 6 observations / questions in your lab log book.''' === Investigation 7: How can I see what network services or ports are active on my CentOS system? === {{Admon/note | Use All Machines | Complete this investigation on all of your VM's and the CentOS host.}}
# Perform this section on your '''c7host''' machine.# On the centos host '''ping''' each of your VM's# Examine the contents of the ARP cache by using the command: <b><code><span style="color:#3366CC;font-size:1.2em;">arp</span></code></b># Check the contents of the cache again by using the command: <b><code><span style="color:#3366CC;font-size:1.2em;">arp -n</span></code></b># What was the difference in output? For what other command did the option '''-n''' have a similar effect?# On your CentOS host execute the command: <b><code><span style="color:#3366CC;font-size:1.2em;">netstat -at</span></code></b>
# This command will list all active TCP ports. Note the state of your ports.
# TCP is a connection oriented protocol that uses a handshaking mechanism to establish a connection. Those ports that show a state of LISTEN are waiting for connection requests to a particular service. For example you should see the <code>'''ssh</code> ''' service in a LISTEN state as it is waiting for connections.# From one of your VM's login to your host using <code>'''ssh</code>'''
# On the CentOS host rerun the command and in addition to the LISTEN port it should list a 2nd entry with a state of ESTABLISHED. This shows that there is a current connection to your ssh server.
# Exit your ssh connection from the VM and rerun the command on the CentOS host. Instead of ESTABLISHED it should now show a state of CLOSE_WAIT. Indicating that the TCP connection is being closed.
# On your CentOS host try the command <b><code><span style="color:#3366CC;font-size:1.2em;">netstat -atn</span></code></b>. How is this output different?# Without the <code>-n</code> option <code>netstat</code> attempts to resolve IP addresses to host names (using '''/etc/hosts''') and port numbers to service names (using '''/etc/services''')# Examine the <code>'''/etc/services</code> ''' file and find which ports are used for the services: <code>'''ssh''', ftp'''sftp''', '''http</code>'''# Now execute the command <b><code><span style="color:#3366CC;font-size:1.2em;">netstat -au</span></code></b> What is the difference between <code>the options: '''-at</code> ''' and <code>'''-au</code>'''?
# When examining UDP ports why is there no state?
'''Answer the Investigation 7 Part 2 observations / questions in your lab log book.'''
== Part 3: Introduction to Firewalls: iptables ==
{| width="40%" align="right" cellpadding="10"
|- valign="top"
|{{Admon/note | | '''[http://en.wikipedia.org/wiki/Iptables Iptables] is the built-in firewall for LINUX'''consisting of a '''list of rules''' (or '''"tables of policies"'''). If data matches a specified <u>policy</u>, it must “jump” to an existing '''condition'''. Simple conditions include '''ACCEPT''', '''DROP''' and '''LOG''' but there are also more complex conditions that can be applied and there is even the option to create your own conditions.
'''INPUT:'''<br>Data is checked against the INPUT chain to see if it is <u>allowed into</u> the PC.<br><br>
'''OUTPUT:'''<br>Data is checked against the OUTPUT chain to see if it is <u>allowed to go outside</u> of the PC.<br><br>
'''FORWARD:'''<br>PC is acting as a router it does not actually send or receive data, it <u>FORWARDS</u> data from one machine to another.
}}
|}
# For the remainder of this section, use your '''c7host''' machine.
# As root on the CentOS host enter the following commands at the prompt:
#* : <codeb>iptables -F</code> (This flushes out or clears all of your rules from the chains)<span style="color:#* <code3366CC;font-size:1.2em;">iptables -L</codespan># You should see something similar to this:<br /code><br /b>Chain INPUT (policy ACCEPT)#: <br /b><br /code>target prot opt source destination<br /span style="color:#3366CC;font-size:1.2em;">iptables -F<br /span>Chain FORWARD (policy ACCEPT)<br /code><br />target prot opt source destination<br /><br />Chain OUTPUT (policy ACCEPT)<br /><br />target prot opt source destination<br /><br /b># What did those commands issued above do? Refer to the ''manpages'' for ''iptables'' if not certain.# Set the default policy for the INPUT chain to DROPby issuing the command:#* : <b><code><span style="color:#3366CC;font-size:1.2em;">iptables -P INPUT DROP</span></code></b># Now try on your own to change the default policies for the OUPUT OUTPUT and FORWARD chains to DROP
# Write the commands you executed in your lab book.
# Can we mix these policies? Try to set the FORWARD chain policy to ACCEPT. Did it work?
# Execute the command <b><code><span style="color:#3366CC;font-size:1.2em;">iptables -L</span></code></b> and check that the policies on your INPUT and OUTPUT chain are set to DROP
# Open a browser and attempt to access the Internet. Were you successful?
# Using the commands you have learned so far, change the policies on the INPUT and OUTPUT chains to ACCEPT
# Open your browser and attempt to access the Internet again. Were you successful?
# Change the policies on all of the chains to DROP
iptables -I OUTPUT -p tcp -s0/0 -d 0/0 --dport 80 -j DROP
Which can be read like this: Insert a rule into the iptables OUTPUT chain that will match any tcp packet, with any a source address, any destination address, and a deistination port of 80. Any packet that matches will be dropped.
'''Let's break down the command to see how it works.:'''
The '''-I''' switch tells iptables to INSERT this line into the OUTPUT policy. This means it will be the first line in the policy. If we used a -A switch it would have appended the line and it would be the last line of the policy. If you are writing complex iptables rules where multiple matches can occur, it is important that the lines go in the right order. If you follow the -I with a number, the new rule will be inserted at that location in the chain (for example, <code>-I 3 OUTPUT</code> will insert the rule into the 3rd position in the OUTPUT chain, moving the existing rules down as necessary (the old rule #3 will become the new rule #4, for example).
}}
|}<ol><li value="6"> In the OUTPUT chain, add the following rule:<br><b><code><span style="color:#3366CC;font-size:1.2em;">iptables -A OUTPUT -j LOG</span></code></b></li><li>The above rule tells '''iptables''' to log packets and relevant information to '''/var/log/messages'''.</li><li>This entry in the OUTPUT policy will therefore log all packets being sent out of the machine.</li><li>Try to access the Internet again. Because the policies have been set to DROP, you should be unsuccessful. However, every packet of data that your PC attempted to send out was logged. Let's have a look at the log file and analyze the data:<br><b><code><span style="color:#3366CC;font-size:1.2em;">tail /var/log/messages</span></code></b></li><li>This command shows us the last 10 lines of the file. While there are many things being logged to this file, the last thing we did was try to access the Internet so we should be able to see the data we need. Look for a line that looks similar to the following:<br /><blockquote><code>Jun 24 12:41:26 c7host kernel: IN= OUT=lo SRC=127.0.0.1 DST=127.0.0.1 LEN=52 TOS=0x00 PREC=0x00 TTL=64 ID=16442 DF PROTO=TCP SPT=57151 DPT=5902 WINDOW=1024 RES=0x00 ACK URGP=0</code></blockquote></li><li>Your IP, host names and date will be different, but the one thing that should be the same is the DPT=80 value.</li><li>When your computer tried to send OUT a request to connect to the Internet using the WWW, the computer used a destination port of 80. This is the standard port for the WWW. Because we have set the default policy to DROP it drops these packets. The problem is we are dropping all packets. What if we just want to drop the WWW packets?</li><li>Using the commands we already know, change the default policies on all of your chains to ACCEPT.</li><li>Open a browser and confirm that you can access the world wide web.</li><li>Enter the command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">iptables -I OUTPUT -p tcp -s0/0 -d 0/0 --dport 80 -j DROP</span></code></b></li><li>Try to access the Web. If you have done everything right, you should not have been successful.</li><li>After you have completed the test execute the following command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">iptables -F</span></code></b><br></li><li>Using the information you have learned, try on your own to achieve the same goal as above (block www access to your computer) by using the INPUT chain instead of the OUTPUT chain.</li><li>After you have completed this task, flush the iptables again.</li><li>Make sure that your ssh server is equivalent running on the host machine and try to:access it from a virtual machine of your choice.</li><li>Once you have confirmed that ssh is running on the host machine, insert an iptables rule on the host machine to prevent access to the ssh server from all VM's on the virtual network.</li><li>Confirm that your rule works by testing from your VM's</li> <li>Does iptables -I OUTPUT -p tcp --dport 80 -j DROPclose the port? Check using '''netstat'''</li><li>Now insert a rule on the CentOS host that would ACCEPT connections from the centos2 VM only.</li><li>Fully test your configuration.</li>}}</ol>
==== Final Tasks =Making iptables Policies Persistent ===
# Make a backup of the file '''/etc/sysconfig/iptables''Answer ' by issuing the Investigation 8 observations command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">iptables-save > / questions in your lab log booketc/sysconfig/iptables.bk</span></code></b>#To make the iptables rules '''persistent''' (i.e. keeps rules when system restarts), you issue the command: <br><b><code><span style="color:#3366CC;font-size:1.2em;">iptables-save > /etc/sysconfig/iptables</span></code></b># Verify that the file '''/etc/sysconfig/iptables''' exists.# Restart your iptables service and test your configuration.
=LAB 6 SIGN-OFF (SHOW INSTRUCTOR) = Completing the {{Admon/important|Time for a new backup, INCLUDING YOUR VIRTUAL HARD DRIVE!|If you have successfully completed this lab ==, make a new backup of your virtual machines. <br><br>'''Virtual hard-drives created lab5 are image files and may have data changed as a result of performing this lab. Therefore, you need to be backed up this hard disk image as well!'''.}}
== Preparing for Practice For Quizzes , Tests, Midterm & Final Exam ==
# What is a port?