Difference between revisions of "OPS335 Lab 5"

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==WEB SERVER RESOURCES==
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[[Category:OPS335]][[Category:OPS335 Labs]]
[[Image:lamp.png|thumb|right|500px|To provide additional help make your web resource more dynamic (for web apps such as webmail) several services are also required. A popular acronym to represent these foundations and servers is referred to as '''LAMP'''. It stands for '''Linux''', '''Apache''', '''MySQL''', and '''PHP''' (or ''Python'').<br><br>Image by Shmuel Csaba Otto Traian,<br>https://commons.wikimedia.org/w/index.php?curid=28224098)<br>(via: [http://creativecommons.org/licenses/by-sa/3.0 Commons Attribution-Share Alike 3.0]) ]]
 
Online References:
 
  
* (Course Notes on the Apache Web Server)
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==OBJECTIVE & PREPARATION==
* [http://www.liquidweb.com/kb/how-to-install-apache-on-centos-7/ Installing Apache Webserver on Centos7]
 
  
 +
This lab's primary focus is to set up a Samba server on a Linux server in order to allow MS Windows users to share common files from the Linux's Samba server.
  
==OVERVIEW==
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This lab will first install, setup, and enable a Samba server. Then users will access files on the Linux Samba server from Linux and Windows client machines (both graphically and command line).
  
In this lab, we will look at several separate technologies that are used with the Apache web server to install, configure and run web applications.
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==INVESTIGATION 1: INSTALLING &amp; CONFIGURING A SAMBA SERVER==
  
The basic purpose of the Apache web server is to serve text pages, images, and other static files. You can format those web-pages to appear nice, but they would lack dynamic functionality (i.e. the ability to change colors or font-size when the mouse moves over a link, button, etc). In other words using Apache web-server as a sole application would not make your web-pages more interesting.
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In this investigation, we will set up a '''Samba server''' on our '''VM2''' machine. We will first install, configure and enable the samba server on our virtual machine, and then we will quickly test to see if the Samba server works.
 
 
If we want to add more features for our web-page (eg. dynamic functionality, security, e-commerce, etc), your webserver would need additional help. To provide additional help requires several resources - more than just the web server itself. A popular acronym to represent these foundations and servers is referred to as '''LAMP'''. It stands for '''Linux''', '''Apache''', '''MySQL''', and '''PHP''' (or ''Python'').
 
 
 
In your previous OPS235 course, your second assignment may have required you setup a similar series of services in order to run a Wiki on one of your virtual machines. In this lab, we will set up another example of a '''"LAMP solution"''' that will allow the user to run webmail in a web-browser to send and receive e-mail messages.
 
 
 
 
 
== INVESTIGATION 1: SETTING UP A LAMP SOLUTION FOR WEBMAIL ==
 
 
 
=== Linux Platform For Webserver (VM4) ===
 
 
 
First, create a new Linux VM that will be contained on the same subnet, using your existing DNS server (''vm1''), and firewall settings.
 
 
 
 
 
{{Admon/tip |Apache Webserver|WIP}}
 
  
  
 
'''Perform the following steps:'''
 
'''Perform the following steps:'''
  
# Create another virtual machine called '''vm4''' from scratch (only a minimal setup is needed). If you forgot how to do this, refer to [http://zenit.senecac.on.ca/wiki/index.php/OPS335_Installation_Lab#VM_Installation Lab1].<br><br>'''For Interest:''' As an optional exercise: configure all your network settings (except the firewall) using the installation wizard during installation static IP<br>(the address '''192.168.X.5''' should be available).<br><br>
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#Make certain that both your '''VM1''' and '''VM2''' machines are running.
# Configure your '''vm4''' virtual machine in the same way that you've configured the other three main VMs. This should be a quick exercise for you by now, including:
+
#Switch to your '''VM2''' machine as the '''root''' user.
::* The Linux installation (minimum install)
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#Issue the following Linux command to install Samba server utlity:<br>'''yum install samba samba-client'''<br>
::* If you didn't setup the network configuration during installation, make certain to connect to the correct network with a static IP<br>(the address 192.168.X.5 should be available),
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#Copy the file '''/etc/samba/smb.conf''' to another filename by issuing the following command:<br>'''cp /etc/samba/smb.conf /etc/samba/smb.conf.original'''
::* Making sure you're using your internal DNS server (make reference to vm4's IPADDR for domain resolution)
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#Clear the contents of the configuration file by running '''cat /dev/null >  /etc/samba/smb.conf'''
::* Configuring default rules for your iptables firewall (hint: use saved shell scripts)
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#Edit '''/etc/samba/smb.conf''' so that the file that contains the following lines:
::* Allowing passwordless login from the host's root account (for future backups)
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[global]
::* Disabling '''selinux''' since you don't know how to configure it properly.<br><br>
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workgroup = WORKGROUP
<ol><li value="3">Test your '''vm4''' virtual machine to make certain that it functions correctly.</li></ol>
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server string = "put your real name here without the quotes"
 +
encrypt passwords = yes
 +
security = user
 +
passdb backend = tdbsam
 +
 +
[home]
 +
comment = "put your real name here without the quotes"
 +
path = /home/<yourSenecaID>
 +
public = no
 +
writable = yes
 +
printable = no
 +
create mask = 0765
 +
 +
[homes]
 +
comment = automatic home share
 +
public = no
 +
writable = yes
 +
printable = no
 +
create mask = 0765
 +
browseable = no
 +
<ol><li value="3">Append (add) the following parameter to the bottom of the '''[global] section''' that will limit access to the share so that only machines in your virtual network will be able to access it:</li></ol>
 +
hosts allow = 192.168.x. 127.0.0.1
 +
<ol><li value="4">Append (add) the following parameter to the '''[home] section''' so that only your user account can access that share:</li></ol>
 +
valid users = <yourSenecaID>
 +
<ol><li value="5">Create a Samba account and password for yourSenecaID by issuing the following command:<br>'''smbpasswd -a <yourSenecaID>'''</li></ol>
  
=== Install, Configure & Run a Webserver (Apache) ===
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{{Admon/tip|Changing Existing Samba Account Passwords|If you need to change a user's existing Samba account password, you can issue the following command as root: '''smbpasswd username'''.}}
  
Next, since we will be running a webmail application, we need to install, configure and run a webserver on our Linux VM.
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<ol><li value="6">Confirm the user you created has been added using the following command:<br>'''pdbedit -L -v'''</li><li>Test and review your configuration with the command:<br>'''testparm'''</li><li>Use the '''systemctl''' command to start the smb.service and enable the service to run on boot-up</li><li>If you have SELinux set to enforcing, you'll will need to tell it to allow samba access to home directories by running: <br> '''setsebool -P samba_enable_home_dirs 1'''</li><li>Use the '''ss -nautp''' command to see with port Samba is running on.</li><li>Use the information in the previous step to modify the firewall on VM2 machine to allow samba traffic.</li><li>Test to see that you can connect to your Samba server (locally) by issuing the following command:<br>'''smbclient -U <yourSenecaID> -L 127.0.0.1'''</li><li>When prompted, enter your Samba account password.</li><li>The output from that issued command show appear similar to example displayed below:</li></ol>
 +
 +
Sharename      Type      Comment
 +
---------      ----      -------
 +
home            Disk      Your Name
 +
IPC$            IPC      IPC Service ("Your Name")
 +
Domain=[WORKGROUP] OS=[Windows 6.1] Server=[Samba 4.2.3]
 +
 +
Server                Comment
 +
------                -------
 +
 +
WorkGroup            Master
 +
---------            ------
 +
 +
<ol><li value="13">To access the Samba client shell on your local Samba share, issue the following command:<br>'''smbclient '\\127.0.0.1\home' -U <yourSenecaID>'''</li><li>Enter your Samba account password.</li><li>Issue the help command to note common commands (''dir'', ''cd'', ''ls'', ''put'', ''get''). Note how similar they are to ''sftp'' commands.</li><li>Enter '''exit''' to terminal your local Samba session.</li></ol>
  
'''Perform the following steps:'''
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You can use smbclient to access, browse and share files within other Linux and Windows servers using a variety of tools which will be demonstrated in Investigations 2 and 3.
 
 
#Make certain you are in your '''VM4''' machine.
 
#Install the Apache package (the name of the package is: '''httpd''').
 
#Start the httpd service, and enable this service to start automatically upon system startup.
 
#Make certain to configure your firewall to allow access to the httpd service (i.e. the Apache serves HTTP traffic which goes over TCP port '''80''').
 
#Open a web-browser in your '''host''' machine and enter the following URL: '''vm4.youruserid.org'''.<br>If you setup your Apache webserver correctly, you should be able to view the Apache Test page.
 
#Delete the file '''/etc/httpd/conf.d/welcome.conf''' to remove the default webpage.
 
#Although we will not be exploring webservers in depth, we will have you create a simple webpage for testing purposes, then later setup a web resource for webmail.
 
#The term'''DocumentRoot''' specifies where the Apache webserver will search for documents to serve. Create the file '''index.html''' in your '''DocumentRoot''' directory with the following contents (replace the date with the current one):
 
 
 
<pre>Hello, this is a web page on vm4.yourid.org and the current time is Mar 28 22:16:27 EDT 2016!</pre>
 
 
 
<ol><li value="9">If you refresh your web-browser page in Firefox, you should see the contents of your ''index.html'' document. If you wish, you can specify the filename index.html in the address, but it is not necessary, since the file index.html is automatically loaded by default when the URL refers to that directory containing that file.</li></ol>
 
  
 +
'''Record steps, commands, and your observations in INVESTIGATION 1 in your OPS335 lab log-book'''
  
{{Admon/tip |Using the '''index.html''' file|It is considered to be a "best practice" to create '''index.html''' files for newly-created subdirectories within the '''DocumentRoot''' (or users' '''public_html''' directories) to force a display of a web-page, instead of viewing the directories "index" listing of files (from "curious eyes"): that is why the name of the file is called ''"index.html"''.}}
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==INVESTIGATION 2: CONNECTING TO A LINUX SMB SERVER FROM A LINUX CLIENT==
  
 +
In this investigation you will explore some of the different ways to access a shared directory from a Linux client machine (VM1).
  
<ol><li value="10">Refresh your web-page by issuing the keycombination: '''ctrl-r'''. Notice that the time doesn't change as you refresh the page. This indicates that the page is static (not dynamic) indicating that the page does not change (i.e. boring!).</li></ol>
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=== Installing and Using smbclient ===
  
=== Creating a PHP Script ===
 
  
In order to allow us to run a webserver application in a web-browser, we need a scripting language that will allow the web-browser to function dynamically (i.e. being able to change frequently, as opposed to being "static" or unchanging). In this section, we will demonstrate how a scripting language (PHP) can be used for the web-browser to react in a more dynamic fashion.
+
'''Perform the following steps on your VM1'''
  
{{Admon/tip |PHP Scripting Language|WIP}}
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#Install the '''samba-client''' and '''cifs-utils''' packages.
 +
#Use the "smbclient" command in a terminal window.<source>
 +
smbclient '\\vm2\home' -U <yourSenecaID></source>
 +
#After entering your password you should get a prompt similar to:<source>
 +
smb: \></source>
 +
#Enter the ls command to see a list of the files in your home directory:<source>
 +
smb: \> ls</source>
 +
#Once you have access to the directory use the get and put commands (similar to ftp) to move files.
 +
#When you are finished close the connection.
 +
# Try again using '''[homes]''' share instead
 +
<source>
 +
smbclient '\\vm2\homes' -U <yourSenecaID></source>
  
'''Perform the following steps:'''
+
Note that this tool only gave temporary access with a limited set of commands.
  
#Replace our '''index.html''' file with an '''index.php''' with the following contents:
+
=== Using 'mount -t cifs' ===
  
<pre>Hello, this is a web page on vm4.yourid.org and the current time is <?php system("date"); ?>!</pre>
+
Instead of always having to use the smbclient command to connect to your network share, you can have the share automatically mounted upon your file server boot-up.
  
<ol><li value="2">On your host machine, again refresh your web-browser. Notice that in a web browser the ''index.php'' file isn't treated as a default page and the contents don't contain the date, but instead are displaying the text in the php code you entered into the index.php file (refer to above code).</li><li>The reason this occurs is that the PHP interpreter hasn't been installed on your Centos vm4 by default.</li><li>Install the php packeage on your vm4 machine. NOTE: The php package comes with a working default Apache configuration so you don't need to enable it manually.</li><li>Refresh the webpage for your web-browser on your host machine. You should now notice that you see the date instead of the call to the date command. Refresh your webpage several times to see how the time changes. This is simply a "trivial example" of dynamic web content does it does provide a simple demonstration of how scripting languages can be used to create more dynamic webpages.</li></ol>
 
  
=== Install, Configure and Run MySQL Database Server ===
+
'''Perform the following steps on your VM1'''
  
We complete the last piece of the puzzle by installing, configuring and running a database server to support your webmail application that will be installed and setup in the next investigation.
+
#Issue the following commands to create a mount-point and to mount your home directory from your vm2 machine:<source>
 +
mkdir /tmp/vm2-home
 +
mount -t cifs //vm2/home /tmp/vm2-home -o username=<yourSenecaID>
 +
ls /tmp/vm2-home</source>
 +
#Create a file in that directory, then switch to '''vm2''' to confirm that it was created.
 +
#Use umount on '''vm1''' to unmount that directory.
  
MySQL is used to allow storage and retrieval of structured data. SQL is a command language (used by scripting languages such as PHP) to allow programmers to access databases contained within a server (or other servers via a network) to be used within web-based applications via the web-browser.
 
  
We won't spend much time learning the details of MySQL configuration but you need a basic server set up. You may remember when setting up MySQL from OPS235 - it is basically the same concept.
+
Note that this tool would leave the directory mounted until the machine rebooted or it was manually unmounted. It would also allow other users access to the directory, as it effectively became part of the local filesystem.  It could even be added to fstab to be mounted on boot (though this would require another configuration file we don't cover).
  
{{Admon/tip |Using MYSQL|WIP}}
+
==INVESTIGATION 3: CONNECTING TO A SAMBA SERVER FROM A WINDOWS CLIENT==
  
'''Perform the following steps:'''
+
This investigation will configure your VM2 machine to act as a Samba File server to allow Windows OS Users access to the Linux Samba server files.
  
#Install '''MySQL''' (you may notice that it's actually called '''MariaDB''' now).<br><br>  The MySQL and MariaDB are actually two <u>separate</u> projects run by different groups, yet they are compatible; therefore, you can use documentation from one to configure the other. <br><br>
+
===Accessing Files on a Linux Samba Server via Windows Explorer ===
#'''NOTE:''' When installing mysql, make certain that you have not just the '''client''' but also the '''server software'''.
 
#When you start the MySQL service, you will receive get some instructions contained in the log file regarding how to set the root password. Even though we will not configure our MySQL service to be accessible over the network, it is accepted as a "best practice" configuring for network access for each MySQL installation.
 
#Note that the MySQL service has two root passwords:<ul><li>For the localhost</li><li>For external requests</li></ul>
 
#Refer to the log file to learn how to run the two commands in order to generate the appropriate passwords.<br><br>NOTE: Use a password you make up yourself, but do <u>not</u> generate a secret password, since you will be storing that password in a plain text file for later reference.
 
#If you have performed the steps in INVESTIGATION 1 correctly, then we can proceed to the next investigation to install, configure and test-out accessing encrypted email messages (performed in labs 4b, 4c, and 4d), but use a convenient webmail application via any web-browser.
 
  
 +
With some additional "tweaking" to your Linux Samba server configuration file, you should be able to access files on that file from a Windows machine on the same network. You will be creating a Samba share for your home directory of your regular user account.
  
'''Record steps, commands, and your observations in INVESTIGATION 1 in your OPS335 lab log-book'''
+
'''Perform the following tasks:'''
  
 +
# Make certain that your '''VM2''' machine is running, is still allowing samba traffic through the firewall, and is still running the samba service.
 +
# Use the Windows machine you are already running Vmware on. If you have a Linux host - good for you, you can either use a Windows VM or skip this part.
 +
# Add the prerouting and forwarding rules to your host's iptables necessary to redirect samba traffic from outside your network to your VM2, making sure to replace the X with your own network address.
 +
::<code>iptables -I FORWARD -p tcp --dport 139 -d 192.168.X.3 -j ACCEPT</code>
 +
::<code>iptables -I FORWARD -p tcp --dport 445 -d 192.168.X.3 -j ACCEPT</code>
 +
::<code>iptables -t nat -A PREROUTING -p tcp --dport 139 -j DNAT --to-destination 192.168.X.3</code>
 +
::<code>iptables -t nat -A PREROUTING -p tcp --dport 445 -j DNAT --to-destination 192.168.X.3</code>
 +
OR with specifing the interface (whichever works):
 +
::<code>iptables -t nat -A PREROUTING -i *externalinterface* -p tcp --dport 139 -j DNAT --to-destination 192.168.X.3</code>
 +
::<code>iptables -t nat -A PREROUTING -i *externalinterface* -p tcp --dport 445 -j DNAT --to-destination 192.168.X.3</code>
 +
where *externalinterface* is an interface name (e.g. ens33)<br>
 +
'''NOTE:''' when you restart libvirtd, it will move your FORWARD rules to the end of the chain, invalidating them.
 +
# Modify the '''hosts allow''' setting on your '''vm2''' to also accept connections from the windows machine you are using.
 +
# Open the Windows File Explorer application.
 +
# At the top of the application, enter the following:<br>'''\\EXTERNAL_IPADDR_OF_HOST\home'''
  
== INVESTIGATION 2: INSTALL, CONFIGURE &amp; RUN WEBMAIL APPLICATION (Roundcube Mail) ==
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{| width="40%" align="right" cellpadding="10"
{|cellpadding="15" width="40%" align="right"
 
  
 
|- valign="top"
 
|- valign="top"
 
+
|
|width="10%" | [[Image:Roundcube.png|thumb|right|300px|'''Roundcube''' webmail application Logo<br>GPL,<br> https://commons.wikimedia.org/w/index.php?curid=1772791]]
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[[Image:samba-login.png|thumb|right|300px|You will be prompted (once only) for the Samba user-name and password for your '''VM2''' machine). ]]
 
+
|
|width="10%" |[[Image:roundcube-screencapture.png|thumb|right|85px|Screencapture of '''roundcube''' webmail application]]
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[[Image:samba3-map-drive.png|thumb|right|300px|You can create a '''mapped network drive (z:)''' for your Linux Samba server network share). ]]
 
 
 
 
 
|}
 
|}
  
 +
<ol><li value="5"> You will be prompted to enter your samba username and password (one time only). Refer to screenshot on right.<br><br>'''NOTE:''' It may take approximately 30 seconds to display the file contents.<br><br></li><li>Were you successful? You should have received an error stating the your credentials are incorrect.  You will notice that it adds SENEDS to the beginning of your user name, as the Seneca machine is pre-configured to be part of that workgroup.</li><li>Change the workgroup parameter in smb.conf on VM2 to match the seneca domain SENEDS, and try to connect again.</li><li>Were you successful? If not, try to troubleshoot the problem first, then ask your lab assistant or instructor for assistance.</li><li>Close the Windows File Explorer application window.</li><li>Click on the '''START''' menu, and click on '''This PC'''.</li><li>Click on the Map Network Drive button, and create a '''mapped network drive''' (called it drive '''Z:''') which is a Samba share of your VM2 machine for the home directory.</li><li>When finished, click on '''Network''' in Windows file manager to confirm that the network share is present.</li><li>Try to create a file on Windows on your Linux Samba machine. Were you able to create a save a file?</li><li>Switch to your VM2 machine and check to see if that file was created in your home directory.</li></ol>
  
In the investigation, we will simply install, configure and run the roundcube webmail application.
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{{Admon/important |Backup your VMs!|You MUST perform a '''full backup''' of ALL of your VMs whenever you complete your '''OPS335 labs''' or when working on your '''OPS335 assignments'''. You should be using the dump or rsync command VMs.}}
 
 
 
 
 
 
'''Perform the following steps:'''
 
 
 
#Perform a search on the roundcube application in order to access the website.
 
#Either Download the "zipped tarball" from their website from a direct link or use the wget command to download directly from a download link (This part may take some effort depending on the Sourceforge website).
 
#Extract the "zipped tarball" and rename the generated directory that contains download source code to: '''webmail'''.
 
#In that directory there will be a file named '''INSTALL''' which will walk you through the rest of the installation.<br><br>Some notes:
 
 
 
::* Be careful about copy-pasting the MySQL setup part, don't try to rush it.
 
::* You'll need to install a couple more Apache modules: php-xml, php-pdo, and php-mysql.
 
::* Don't forget to set the password in the roundcube configuration.
 
 
 
<ol><li value="3">Note that both your IMAP and SMTP servers are on different machines, not on vm4. For that to work you'll need to set the following options for Roundcube:</li></ol>
 
 
 
::* $config['smtp_server']
 
::* $config['default_host']
 
::* $config['default_port']
 
 
 
:::(the last two are your IMAP server)
 
 
 
 
 
<ol><li value="4">You should be able to test the configuration in your Roundcube installer Step 3.</li></ol>
 
 
 
'''Record steps, commands, and your observations in INVESTIGATION 2 in your OPS335 lab log-book'''
 
  
 +
'''Record steps, commands, and your observations from this INVESTIGATION in your OPS335 lab log-book'''
  
== COMPLETING THE LAB ==
+
==COMPLETING THE LAB==
 +
In completing this lab you have gained experience using a service that allows remote access to files stored on a Linux server.  You have also learned how to use several different tools to access those files, both from a Linux and Windows client..
  
Students should be prepared with '''all required commands (system information) displayed in a terminal (or multiple terminals) prior to calling the instructor for signoff'''.
+
===Online Submission===
 +
Follow the instructions for lab 5 on blackboard.
 +
<!--
 +
===Andrew's sections===
  
'''Arrange evidence (command output) for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:'''
+
You may choose to:
 +
* Submit screenshots of your work on Blackboard, in which case you don't need to come to the lab.
 +
* Or come to the lab, show me your work, and talk to me about it. I want to hear what you've learned and answer any questions you have.
  
::<span style="color:green;font-size:1.5em;">&#x2713;</span>Your webmail showing your inbox
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You'll get the same grade regardless of how you choose to submit your work.
::<span style="color:green;font-size:1.5em;">&#x2713;</span>Your webmail sending an email out
 
::<span style="color:green;font-size:1.5em;">&#x2713;</span>You receiving that mail on an exernal account
 
  
 +
::<span style="color:green;font-size:1.5em;">&#x2713;</span> Proof of network share of VM2 machine from Windows VM via Windows Explorer application
 +
::<span style="color:green;font-size:1.5em;">&#x2713;</span> Firewall settings on your Windows VM to allow Linux Samba network share
 +
::<span style="color:green;font-size:1.5em;">&#x2713;</span> Display contents of '''/etc/samba/smb.conf''' file on VM2 machine
 +
::<span style="color:green;font-size:1.5em;">&#x2713;</span> Firewall exceptions (both machines) to allow Samba traffic
 +
::<span style="color:green;font-size:1.5em;">&#x2713;</span>Download and run '''https://ict.senecacollege.ca/~andrew.smith/ops335/labcheck5.bash'''
 +
::<span style="color:green;font-size:1.5em;">&#x2713;</span>Completed Lab5 log-book notes.
 +
-->
  
 
==EXPLORATION QUESTIONS==
 
==EXPLORATION QUESTIONS==
  
  
#
+
#What does SMB stand for?
 +
#What does CIFS stand for?
 +
#What is the purpose of the '''testparm''' command?
 +
#What does the text inside square brackets in the '''smb.conf''' file mean? (e.g., "[home]").
 +
#Explain the meaning of the line "create mask = 0765" in the smb.conf file?
 +
#What does the '''smbpasswd''' command do?

Latest revision as of 20:32, 4 January 2021


OBJECTIVE & PREPARATION

This lab's primary focus is to set up a Samba server on a Linux server in order to allow MS Windows users to share common files from the Linux's Samba server.

This lab will first install, setup, and enable a Samba server. Then users will access files on the Linux Samba server from Linux and Windows client machines (both graphically and command line).

INVESTIGATION 1: INSTALLING & CONFIGURING A SAMBA SERVER

In this investigation, we will set up a Samba server on our VM2 machine. We will first install, configure and enable the samba server on our virtual machine, and then we will quickly test to see if the Samba server works.


Perform the following steps:

  1. Make certain that both your VM1 and VM2 machines are running.
  2. Switch to your VM2 machine as the root user.
  3. Issue the following Linux command to install Samba server utlity:
    yum install samba samba-client
  4. Copy the file /etc/samba/smb.conf to another filename by issuing the following command:
    cp /etc/samba/smb.conf /etc/samba/smb.conf.original
  5. Clear the contents of the configuration file by running cat /dev/null > /etc/samba/smb.conf
  6. Edit /etc/samba/smb.conf so that the file that contains the following lines:
[global]
workgroup = WORKGROUP 
server string = "put your real name here without the quotes"
encrypt passwords = yes
security = user
passdb backend = tdbsam

[home]
comment = "put your real name here without the quotes"
path = /home/<yourSenecaID>
public = no
writable = yes
printable = no
create mask = 0765

[homes]
comment = automatic home share
public = no
writable = yes
printable = no
create mask = 0765
browseable = no
  1. Append (add) the following parameter to the bottom of the [global] section that will limit access to the share so that only machines in your virtual network will be able to access it:
hosts allow = 192.168.x. 127.0.0.1
  1. Append (add) the following parameter to the [home] section so that only your user account can access that share:
valid users = <yourSenecaID>
  1. Create a Samba account and password for yourSenecaID by issuing the following command:
    smbpasswd -a <yourSenecaID>
Idea.png
Changing Existing Samba Account Passwords
If you need to change a user's existing Samba account password, you can issue the following command as root: smbpasswd username.
  1. Confirm the user you created has been added using the following command:
    pdbedit -L -v
  2. Test and review your configuration with the command:
    testparm
  3. Use the systemctl command to start the smb.service and enable the service to run on boot-up
  4. If you have SELinux set to enforcing, you'll will need to tell it to allow samba access to home directories by running:
    setsebool -P samba_enable_home_dirs 1
  5. Use the ss -nautp command to see with port Samba is running on.
  6. Use the information in the previous step to modify the firewall on VM2 machine to allow samba traffic.
  7. Test to see that you can connect to your Samba server (locally) by issuing the following command:
    smbclient -U <yourSenecaID> -L 127.0.0.1
  8. When prompted, enter your Samba account password.
  9. The output from that issued command show appear similar to example displayed below:
Sharename       Type       Comment
---------       ----       -------
home             Disk      Your Name
IPC$             IPC       IPC Service ("Your Name")
Domain=[WORKGROUP] OS=[Windows 6.1] Server=[Samba 4.2.3]

Server                Comment
------                -------

WorkGroup             Master
---------             ------

  1. To access the Samba client shell on your local Samba share, issue the following command:
    smbclient '\\127.0.0.1\home' -U <yourSenecaID>
  2. Enter your Samba account password.
  3. Issue the help command to note common commands (dir, cd, ls, put, get). Note how similar they are to sftp commands.
  4. Enter exit to terminal your local Samba session.

You can use smbclient to access, browse and share files within other Linux and Windows servers using a variety of tools which will be demonstrated in Investigations 2 and 3.

Record steps, commands, and your observations in INVESTIGATION 1 in your OPS335 lab log-book

INVESTIGATION 2: CONNECTING TO A LINUX SMB SERVER FROM A LINUX CLIENT

In this investigation you will explore some of the different ways to access a shared directory from a Linux client machine (VM1).

Installing and Using smbclient

Perform the following steps on your VM1

  1. Install the samba-client and cifs-utils packages.
  2. Use the "smbclient" command in a terminal window.
     smbclient '\\vm2\home' -U <yourSenecaID>
  3. After entering your password you should get a prompt similar to:
     smb: \>
  4. Enter the ls command to see a list of the files in your home directory:
     smb: \> ls
  5. Once you have access to the directory use the get and put commands (similar to ftp) to move files.
  6. When you are finished close the connection.
  7. Try again using [homes] share instead
 smbclient '\\vm2\homes' -U <yourSenecaID>

Note that this tool only gave temporary access with a limited set of commands.

Using 'mount -t cifs'

Instead of always having to use the smbclient command to connect to your network share, you can have the share automatically mounted upon your file server boot-up.


Perform the following steps on your VM1

  1. Issue the following commands to create a mount-point and to mount your home directory from your vm2 machine:
     mkdir /tmp/vm2-home
     mount -t cifs //vm2/home /tmp/vm2-home -o username=<yourSenecaID>
     ls /tmp/vm2-home
  2. Create a file in that directory, then switch to vm2 to confirm that it was created.
  3. Use umount on vm1 to unmount that directory.


Note that this tool would leave the directory mounted until the machine rebooted or it was manually unmounted. It would also allow other users access to the directory, as it effectively became part of the local filesystem. It could even be added to fstab to be mounted on boot (though this would require another configuration file we don't cover).

INVESTIGATION 3: CONNECTING TO A SAMBA SERVER FROM A WINDOWS CLIENT

This investigation will configure your VM2 machine to act as a Samba File server to allow Windows OS Users access to the Linux Samba server files.

Accessing Files on a Linux Samba Server via Windows Explorer

With some additional "tweaking" to your Linux Samba server configuration file, you should be able to access files on that file from a Windows machine on the same network. You will be creating a Samba share for your home directory of your regular user account.

Perform the following tasks:

  1. Make certain that your VM2 machine is running, is still allowing samba traffic through the firewall, and is still running the samba service.
  2. Use the Windows machine you are already running Vmware on. If you have a Linux host - good for you, you can either use a Windows VM or skip this part.
  3. Add the prerouting and forwarding rules to your host's iptables necessary to redirect samba traffic from outside your network to your VM2, making sure to replace the X with your own network address.
iptables -I FORWARD -p tcp --dport 139 -d 192.168.X.3 -j ACCEPT
iptables -I FORWARD -p tcp --dport 445 -d 192.168.X.3 -j ACCEPT
iptables -t nat -A PREROUTING -p tcp --dport 139 -j DNAT --to-destination 192.168.X.3
iptables -t nat -A PREROUTING -p tcp --dport 445 -j DNAT --to-destination 192.168.X.3

OR with specifing the interface (whichever works):

iptables -t nat -A PREROUTING -i *externalinterface* -p tcp --dport 139 -j DNAT --to-destination 192.168.X.3
iptables -t nat -A PREROUTING -i *externalinterface* -p tcp --dport 445 -j DNAT --to-destination 192.168.X.3

where *externalinterface* is an interface name (e.g. ens33)
NOTE: when you restart libvirtd, it will move your FORWARD rules to the end of the chain, invalidating them.

  1. Modify the hosts allow setting on your vm2 to also accept connections from the windows machine you are using.
  2. Open the Windows File Explorer application.
  3. At the top of the application, enter the following:
    \\EXTERNAL_IPADDR_OF_HOST\home
You will be prompted (once only) for the Samba user-name and password for your VM2 machine).
You can create a mapped network drive (z:) for your Linux Samba server network share).
  1. You will be prompted to enter your samba username and password (one time only). Refer to screenshot on right.

    NOTE: It may take approximately 30 seconds to display the file contents.

  2. Were you successful? You should have received an error stating the your credentials are incorrect. You will notice that it adds SENEDS to the beginning of your user name, as the Seneca machine is pre-configured to be part of that workgroup.
  3. Change the workgroup parameter in smb.conf on VM2 to match the seneca domain SENEDS, and try to connect again.
  4. Were you successful? If not, try to troubleshoot the problem first, then ask your lab assistant or instructor for assistance.
  5. Close the Windows File Explorer application window.
  6. Click on the START menu, and click on This PC.
  7. Click on the Map Network Drive button, and create a mapped network drive (called it drive Z:) which is a Samba share of your VM2 machine for the home directory.
  8. When finished, click on Network in Windows file manager to confirm that the network share is present.
  9. Try to create a file on Windows on your Linux Samba machine. Were you able to create a save a file?
  10. Switch to your VM2 machine and check to see if that file was created in your home directory.
Important.png
Backup your VMs!
You MUST perform a full backup of ALL of your VMs whenever you complete your OPS335 labs or when working on your OPS335 assignments. You should be using the dump or rsync command VMs.

Record steps, commands, and your observations from this INVESTIGATION in your OPS335 lab log-book

COMPLETING THE LAB

In completing this lab you have gained experience using a service that allows remote access to files stored on a Linux server. You have also learned how to use several different tools to access those files, both from a Linux and Windows client..

Online Submission

Follow the instructions for lab 5 on blackboard.

EXPLORATION QUESTIONS

  1. What does SMB stand for?
  2. What does CIFS stand for?
  3. What is the purpose of the testparm command?
  4. What does the text inside square brackets in the smb.conf file mean? (e.g., "[home]").
  5. Explain the meaning of the line "create mask = 0765" in the smb.conf file?
  6. What does the smbpasswd command do?