Difference between revisions of "OPS335 Lab 5"

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In this lab we will have a quick look at several separate technologies that are often used together with the Apache web server to install and run web applications.
+
[[Category:OPS335]][[Category:OPS335 Labs]]
  
Apache on its own does little more than serve text pages, images, and other static files. You can format those pages to look nice but they won't have any dynamic functionality - they will always look the same.
+
==OBJECTIVE & PREPARATION==
  
To add life to a website more than just the web server is needed. A popular acronym is LAMP. It stands for Linux, Apache, MySQL, and PHP (or Python). This week we will set up this stack to give us a website that does webmail (send and receive email in a web browser).
+
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.
  
= LAMP =
+
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).
== Linux ==
 
  
We'll need a new virtual machine. Because you probably forgot how to install one - go through the exercise again, and set up a vm4 from scratch. Only a minimal setup is needed. Configure it in the same way that you've configured the other three main VMs. This should be a quick exercise for you by now, including:
+
==INVESTIGATION 1: INSTALLING & CONFIGURING A SAMBA SERVER==
* The installation,
 
* Connecting to the correct network with a static IP (the address 192.168.X.5 should be available),
 
* Making sure you're using your internal DNS server,
 
* Configuring default rules for your iptables firewall,
 
* Allowing passwordless login from the host's root account,
 
* Disabling selinux since you don't know how to configure it properly.
 
  
As an interesting exercise: configure all your network settings (except the firewall) during the installation wizard.
+
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.
  
== Apache ==
 
  
Install Apache (the package name is httpd), start the service, make it start automatically, and allow access to it through the firewall (Apache serves HTTP traffic which goes over TCP port 80).
+
'''Perform the following steps:'''
  
Now if you navigate to vm4.youruserid.org in a web browser in your host - you should see an Apache testing page.
+
#Make certain that both your '''VM1''' and '''VM2''' machines are running.
 +
#Switch to your '''VM2''' machine as the '''root''' user.
 +
#Issue the following Linux command to install Samba server utlity:<br>'''yum install samba samba-client'''<br>
 +
#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'''
 +
#Clear the contents of the configuration file by running '''cat /dev/null >  /etc/samba/smb.conf'''
 +
#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
 +
<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>
  
Delete the file '''/etc/httpd/conf.d/welcome.conf''' to get rid of the default page.
+
{{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'''.}}
  
We're not going to have a lot of time to study various Apache options so we'll tell you what you're looking for but you have to find it yourself.
+
<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>
  
'''DocumentRoot''' specifies where Apache will look for documents to serve.
+
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.
  
Now create the file '''index.html''' in your DocumentRoot directory with the following contents (replace the date with the current one):
+
'''Record steps, commands, and your observations in INVESTIGATION 1 in your OPS335 lab log-book'''
  
<pre>Hello, this is a web page on vm4.yourid.org and the current time is Mar 28 22:16:27 EDT 2016!</pre>
+
==INVESTIGATION 2: CONNECTING TO A LINUX SMB SERVER FROM A LINUX CLIENT==
  
If you refresh the page in Firefox - you should see the contents of your index.html. If you like - you can specify the filename index.html in the address but there's no need since it's a default.
+
In this investigation you will explore some of the different ways to access a shared directory from a Linux client machine (VM1).
  
It may seem obvious - but notice that the time doesn't change as you refresh the page.
+
=== Installing and Using smbclient ===
  
== PHP ==
 
  
We'll replace our '''index.html''' file with an '''index.php''' with the following contents:
+
'''Perform the following steps on your VM1'''
  
<pre>Hello, this is a web page on vm4.yourid.org and the current time is <?php system("date"); ?>!</pre>
+
#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>
  
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 have exactly the text above. That's because the PHP interpreter isn't installed by default on CentOS. Install it. The package comes with a working default Apache configuration so you don't need to enable it manually.
+
Note that this tool only gave temporary access with a limited set of commands.
  
Refresh the page, notice that you now see the date instead of the call to the date command. This is a trivial example of dynamic web content - it doesn't need to be the same every time you look at it.
+
=== Using 'mount -t cifs' ===
  
== MySQL ==
+
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'''
 +
 
 +
#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.
 +
 
 +
 
 +
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:'''
 +
 
 +
# 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'''
 +
 
 +
{| width="40%" align="right" cellpadding="10"
 +
 
 +
|- valign="top"
 +
|
 +
[[Image:samba-login.png|thumb|right|300px|You will be prompted (once only) for the Samba user-name and password for your '''VM2''' machine). ]]
 +
|
 +
[[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>
 +
 
 +
{{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.}}
 +
 
 +
'''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.
 +
<!--
 +
===Andrew's sections===
 +
 
 +
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.
 +
 
 +
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> 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==
 +
 
 +
 
 +
#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 19:32, 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?