= Install and Configure a DHCP Server =[[Category:OPS235]][[Category:OPS235 Labs]]{{Admon/caution|Draft Lab|This lab has NOT been released for regular distribution. When the lab is ready to be released, this caution banner will disappear.}}= Setting Up, Using & Maintaining a DHCP Server =

* To install, configure, and test ISC's DHCP Server.* To obtain log information from DHCP server including lease address information.* To lease the same IP address every-time from VM boot-up (instead of having DHCP server randomly assign IP address). ==Required Materials (Bring to All Labs)== * Fedora 17 LIVE CD* Fedora 17 x86_64 Installation DVD* SATA Hard Disk (in removable disk tray)* USB Memory Stick* Lab Logbook ==Prerequisites== * Completion and Instructor "Sign-off" of Lab 7: [[OPS235 Lab 7]] 

== Linux Command Online Reference ==Each Link below displays online manpages for each command (via [http://linuxmanpages.com/ http://linuxmanpages.com]): {|width="100%" cellpadding="5" width="50%"|'''Networking Utilities:'''|'''Additional Utilities:'''|'''Configuration Files:'''|- valign="top"| *[http://linuxmanpages.com/man8/dhcpd.8.php dhcpd]* [http://linuxmanpages.com/man8/ifconfig.8.php ifconfig]|*[http://www.linuxcertif.com/ man pages/1/systemctl/ systemctl]*[http://linuxmanpages.com/man1/tail.1.php tail] for |*[http://linuxmanpages.com/man5/dhcpd, .conf.5.php dhcpd.conf, dhcpd]*[http://linuxmanpages.leases, com/man5/dhcp-options, dhclient, dhclient.5.php dhcpd-confoptions]*[http://linuxmanpages.com/man5/dhcpd.leases.5.php dhcpd.leases]|}  ==Resources on the web==Additional links to tutorials and HOWTOs:

== Install and Configure a DHCP Server == === Lab Preparation ===

{{Admon/note |ISC DHCP packages Overview | The version of DHCP server (rpm package name called "'''dhcp-4.1.1-9.fc12fc16.x86_64" ''' ) that comes with Fedora is maintained and distributed by the Internet Software Consortium (http://www.isc.org). The source package that you can download from ISC includes not only the DHCP server, but also a DHCP client and a DHCP relay agent. However, Fedora separates it into two RPM packages: the DHCP client package called "'''dhclient-4.1.1-9.fc12fc16.x86_64" ''' and the DHCP server package called "'''dhcp-4.1.1-9.fc12fc16.x86_64"'''. The DHCP client package is installed by default by the workstation installation.}}

== Completing the Lab ===== Investigation 1: How do you install the DHCP Server. ? ==={{Admon/note | Note! Use your fedora3 VM | Complete the following steps on your fedora3 VM.}}

{{Admon/note | Note! Use your fedora3 VM | Complete the following steps on your fedora3 VM.}}

{{Admon/note | Note! Use your fedora3 VM | Complete the following steps on your fedora3 VM.}}

::* <code>domain-name</code> should be set to "'''ops235.org"'''::* <code>domain-name-servers</code> should be set to '''192.168.235.1'''::* <code>default-lease-time</code> should be set to '''20 minutes'''::* <code>max-lease-time</code> should be set to '''1 hour'''<ol><li value="23"> Answer the Investigation 3 question in Save and exit your log bookediting session.</li>

{{Admon/note | Note! Global Settings Affecting All Subnets | As global settings , these settings will affect <u>'''all subnets '''</u> unless they are separately declared for individual subnets.}} '''Answer the Investigation 3 observations / questions in your lab log book.''' 

{{Admon/note | Note! Use your fedora3 VM | Complete the following steps on your fedora3 VM.}}

* # Edit <code>/etc/dhcp/dhcpd.conf</code> for a second time, and add a new subnet delcaration for your virtual network* # The network address is '''192.168.235.0/255.255.255.0 ''' and the range of host addresses should be from '''51 to 60'''* # Also add a default gateway for the virtual network of '''192.168.235.1'''* # Save your editing session, and exit the filetext editor.{{Admon/note | Recall Secure SSH Connection Method from Lab7 | Do not forget that you [http://zenit.senecac.on.ca/wiki/index.php/OPS235_Lab_7#Investigation_7:_How_do_you_make_sshd_more_secure. made ssh more secure] in the previous lab. Therefore, you will need to use the same command in lab7 to securely connect to your VM.}} * <ol><li value="5">Open another terminal window (ssh into fedora3 from fedora host as user root) and issue the following command:** ::: <code>tail -f /var/log/messages</code>* <li>This will show you the last 10 lines of <code>/var/log/messages</code> continue to display new lines as they are added to the log.</li>* <li>In your original terminal prompt attempt to start the <code>dhcpd</code> service.</li>* <li>You should see new lines being added to the messages file.</li>* <li>If the <code>dhcpd</code> service fails to start any error messages will be logged in the messages file. Read the errors and attempt to fix your configuration file.</li>* <li>If the <code>dhcpd</code> service starts successfully you should see success messages in the log. </li>* <li>If your <code>dhcpd</code> service starts successfully edit , try to generate errors by editing the configuration file and introduce an error by removing a semicolon or closing curly bracket.</li>* <li>Restart your <code>dhcpd</code> service and observe the error messages generated.This is good practice to learn how to trouble-shoot and solve dhcpd errors.</li><li>Make certain that you have corrected those errors, and that your dhcpd service works properly.</li></ol>

* When you have successfully started your service answer  '''Answer the Investigation 4 question observations / questions in your lab log book. You may want to include all of the syntax you used.''' 

* {{Admon/note | Use your fedora2 and fedora3 VMs | Complete the following steps on your fedora2 and fedora3 VM's.}} # On a fedora3 terminal window make sure that the command <code>tail -f /var/log/messages</code> is running.* # On your fedora2 VM, change the configuration of the '''eth1 ''' (or your interface name) to receive dynamic address configuration.* # Save your changes and restart the <code>NetworkManager</code>service.* # Observe the messages that get logged. You should see output similar to the following:<pre>

{{Admon/note | Note! Identifying DHCP Lease Transaction Information | These messages record the DHCP lease transaction that consists of 4 broadcast packets, DISCOVER, OFFER, REQUEST and ACKNOWLEDGE. Try researching on the internet how this transaction differs from a DHCP lease renewal.}}* <ol><li value="5">On fedora2 , confirm the IP address assignment using <code>ifconfig</code></li>* </ol> '''Answer the Investigation 5 question observations / questions in your lab log book.'''   == Obtaining Lease Information &amp; Lease Permanent IP Address ==

* {{Admon/note | Use your fedora2 and fedora3 VMs | Complete the following steps on your fedora2 and fedora3 VM's.}} # If your fedora3 DHCP server successfully issued the proper IP address configuration values to fedora2, check the file called <code>/var/lib/dhcpd/dhcpd.leases</code>* # You should see contents similar to:

{{Admon/note | Note! Purpose of <code>dhcpd.leases</code> File | dhcpd records address leases in this file. If the service is restarted it reads in the file to know which addresses are currently leased and for how long.}}* <ol><li value="3">On the client fedora2 check the contents of the<code>/var/lib/dhclient</code> directory. The files in this directory is where the dhclient stores its record of leases.</li></ol>* '''Answer the Investigation 6 question observations / questions in your lab log book.'''

{{Admon/note | Note! Use your fedora2 and fedora3 VMs | Complete the following steps on your fedora2 and fedora3 VM's.}} {{Admon/note | Reserving IP Addresses with DHCP | Even though DHCP gives out IP address dynamically, it also has the ability to reserve an IP address for a certain computer. In this sense it's almost as if the client computer has a static IP even though it uses DHCP to get it. This is useful if you want to be able to put entries in your /etc/hosts file and not have to worry about the entry becoming invalid over time. In Linux we refer to this as supplying a fixed address to a host. Microsoft calls it a reservation.}} # Make certain that you are located in your fedora3 virtual machine.# Create a host declaration for fedora2. Make sure you record the correct <code>hardware ethernet</code> setting that corresponds to the MAC address of the interface in fedora2.# Give it the fixed-address 192.168.235.12{{Admon/tip | Avoiding IP Address Conflicts | When supplying fixed-address it is important that the address assigned is exclusive of any ranges that have been declared. Otherwise it may be possible for 2 different hosts to receive the same address.}}<ol><li value="3">Start your service and test the address assignment by releasing your current address on fedora2 and then requesting a new address. Use the following commands on fedora2:</li></ol>::: <code>ifdown eth1</code>::: <code>ifup eth1</code><ol><li value="4">Confirm that you received the fixed address you were supposed to.</li></ol>

* Create a host declaration for fedora2. Make sure you record the correct <code>hardware ethernet</code> setting that corresponds to the MAC address of the interface in fedora2.* Give it the fixed-address 192.168.235.12{{Admon/tip | Note! | When supplying fixed-address it is important that the address assigned is exclusive of any ranges that have been declared. Otherwise it may be possible for 2 different hosts to receive the same address.}}* Start your service and test the address assignment by releasing your current address on fedora2 and then requesting a new address. Use the following commands on fedora2:** <code>dhclient -r eth1</code>** <code>dhclient eth1</code>* Confirm that you received the fixed address you were supposed to.* '''Answer the Investigation 7 question observations / questions in your lab log book.'''

== Preparing for the Quizzes ==

* # What protocol and port does dhcp use? * # What file is used to configure dhcpd?* # Can a dhcp server also be a dhcp client?* # What is the difference between max-lease-time and default-lease-time?* # What unit of measurement does default-lease-time require?* # What dhcp option is used for configuring a default gateway?* # What is the parameter range in the DHCP server configuration file used for? * # What is the purpose of a dhcp relay agent?* # Why might a dhcp relay agent be required?