OPS335 Web Server Lab

FILE SERVER RESOURCES

Online References:

Basic Apache (Web Server) Setup

This lab will show you how to set up the Apache Web server using a Fedora 22 installed PC.

Prerequisites

Your hard drive should have Centos 7, 64 bit already installed.
You have Fedora 22, 64bit version on VM1, VM2, and VM3.
Both your host and all VMs should have SELinux enabled.
Both host and all VMs should have all software updated.

Ensure the clocks on both machines are set to the correct date and time.

Testing your network

• Start Firefox on your host and authenticate yourself on Senenet.
• Ensure you can access the web on your host machine and all your VMs.

Install and test Apache on your VM1 and VM3

• Login to vm1 and install the following packages:

 dnf install httpd httpd-tools

• Still on vm1 you can now start your web server with this command and enable the service to start at boot.

systemctl start httpd.service
systemctl enable httpd.service

• Using a text browser such as lynx on vm1 go to localhost. You should get the "Fedora Test Page" which indicates your web server is running on the local virtual machine.
• Make sure the firewall still meets the specifications set out in the earlier labs and add a rule to allow incoming traffic to your http server.
• Using Firefox on the host go to address for vm1 "192.168.X.2" (your ip addressing may differ). You should get the "Fedora Test Page" which indicates you can access your web server on VM1 via network connection. Do not continue until this step works.
  • Once you have this working, save your firewall.
• You should also be able to open the webpage using the hostname of vm1.
• Now create your own test page named index.html in the directory /var/www/html/. This does not have to anything fancy, just a valid html page with enough content for you to recognize it as your own. Reload the web page on the host - you should see your own test page now instead of the default page from apache.
• Repeat the above steps for vm3.
• Now, as root on the gateway/host, try to forward incoming http connections to your host to the web server on vm1. Use an iptables command something like this

iptables -t nat -A PREROUTING -i *yourinterface* -p tcp --dport 80 -j DNAT --to 192.168.X.2

• You will also need to create a rule in the FORWARD chain in the default table to accept connections to port 80.
• To test this setup you'll need to ask a classmate on another PC to try to use Firefox to view your web page. S/he'll have to enter your host's external interface IP number in Firefox's address window.
• Login to your vm1 (and then vm3) as root, edit the Apache configuration file and change the port your webserver is listening for incoming connections from 80 to 8080.

vi /etc/httpd/conf/httpd.conf

• Change your firewall rules on vm1 (and also vm3) to allow connections to this port (8080), and remove the previous rule to allow connections to port 80.
• Restart the apache server on vm1 and vm3 (this may take a minute).
• Go back to the host and redo your iptables command to forward connections to port 80 (on your host) to the new port 8080 on vm1, removing the previous rule for port 80.
• Verify that other students on their PCs can still view your web page.

Load balancing using iptables

• Iptables can be used for load balancing connections. On your host machine add a rule(s) to the PREROUTING chain that will alternate connections bound for port 80 on your host machine to vm1 and vm3 (remove the other prerouting rules you created before doing this).

iptables -t nat -I PREROUTING -p tcp --dport 80 -m state --state NEW -m statistic --mode nth --every 2 --packet 1 -j DNAT --to-destination 192.168.X.4:8080
iptables -t nat -I PREROUTING -p tcp --dport 80 -m state --state NEW -m statistic --mode nth --every 2 --packet 0 -j DNAT --to-destination 192.168.X.2:8080

• Again ask another student to test that load balancing is indeed working.

Add missing DNS resource records

• Edit your forward look-up zone file and add the following resource records.
  • A mail exchange record that points mail for the domain to vm2.
  • Alases as follows:
    • host - alias router
    • vm2 - alias mail
    • vm1 - alias www1
    • vm3 - alias www2
  • Add text records that identify the roles on each of these machines and a text record for the domain "This is < your full name here>'s OPS335 Domain".
  • Once these records have been added, be sure to increment your Serial number for the zone file. While not crucial for the lab as we do not yet have a slave DNS server, getting into the habit ensures slaves will be informed of the changes.
  • Use the tools you have learned in earlier labs (e.g. ping, host, lynx, etc.) to make sure these records work.

Adding Webmail to your domain

• In order for our domain to offer webmail services to its users you will need to install the following packages on vm2

dnf install squirrelmail httpd dovecot

• The SquirrelMail files are in /usr/share/squirrelmail, create the a symbolic link to share those files on the internet.

ln -s /usr/share/squirrelmail /var/www/html/mail

• Change directories and run the configuration script for SquirrelMail

cd /usr/share/squirrelmail/config
./conf.pl

• Use the menu to select #2 - Server Settings. Edit #1 Domain - choosing your domain name, and #3 Selecting SMTP. Ensure you have saved the data then return to the main menu. From the main menu select option D - Set pre-defined settings for specific IMAP servers, then enter 'dovecot'.
• From the main menu select '1. Organization Preferences', then select option #1 'Organization Name' and change this to your domain name.
• Check The Postfix configuration file and find the below line and make sure "$mydomain" is listed to ensure delivery of emails sent to the domain and not just the host name.

mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

• Edit the dovecot configuration file (use dovecot -n to find out where it is) and uncomment the following line

protocols = imap pop3 lmtp

• And add to the bottom of the file

mail_location = mbox:~/mail:INBOX=/var/mail/%u

• You will need to change the permissions on the mail directories for the users from the default 660 to 600.

chmod 0600 /var/mail/*

• you should now start and enable dovecot, httpd and restart postfix if it was already running.
• test your connection to SquirrelMail by opening a browser and navigating to vm2/mail. You should see a log in page. Sign in using your non-privileged login credentials on vm2.
  • You may receive an error stating: 'Error connecting to IMAP server: localhost. 13 : Permission denied'. If you do, run the command 'setsebool -P httpd_can_network_connect=1'. This will set an SELinux boolean to allow httpd connections across the network.
• You will need to open ports on your firewall to allow connections to the webserver, and adjust the port forwarding on the host so that any web traffic sent to it will be redirected to your VM2.
• If everything is configured properly but you still get permission denied errors - disable SELinux on vm2.

Completing the Lab

Upon completing this lab you have gained experience in balancing traffic between several servers, and in routing traffic from one server to another. You have also made use of some more advanced resource records in your DNS server.

Remove the prerouting rules that were balancing web traffic between your VMs. While the rules themselves are fine, the iptables-save command will break them when it saves them, preventing your tables from working properly.

Exploration questions:

1. Where are the apache log files stored? What does each one log?
2. What does the server root parameter determine? What is its default value?
3. What does the document root parameter determine? What is its default value?
4. What is the default configuration file for the Apache web server on Fedora 22? Give the absolute path.
5. What is the maximum number of connections allowed on the server by default?
6. What user/group does Apache run under on Fedora 22?
7. What % share of the web server market was running apache as of September 2015?
8. What specific command (give full details) would you need to use on your host to forward all ssh connections to vm1?
9. What is the web site for Apache?
10. What is Apache's highest version number? What is the version running on your system?