Some documentation to get started with (you'll need to find more)Online References: 

This lab will show you how to set up a '''Postfix ''' email server using a Fedora 20 installation('''MTA''') on your '''VM2''' and '''VM3''' machines.*You will need at least two systems also be setting up on your '''VM2''' and '''VM3''' machines the '''mailx''' package ('''MUA''') to do this laballow users to send and receive text-based mail messages. If for some reason you have not set up You should also be able to send email messages to your virtual machines, do so before continuingSeneca College email account. The diagram below shows the layout of the what this lab should be able to accomplish: 

==INVESTIGATION 1: INSTALL & SETUP THE MAIL TRANSFER AGENT (MTA) USING POSTFIX==

#Start Firefox on your host and authenticate yourself on Senenet with your Seneca account.#Ensure Make certain that you can surf connect to the web Internet on your host machineHost Machine via web-browser. As Since your host should be using VM 1 '''VM1''' as its '''DNS server''', you will need to start it make certain that the VM1 machine is running as well.#Ensure Start Firefox on your Host Machine, and access your Seneca e-mail account (https://myseneca.ca).#Confirm that you can access the web on from your VM2 (you machine. You can use install the wget or lynx applications in order to test this for that). your text-based server (NOTE: you should not have to authenticate yourself on the guestmachine). ===Install and configure Postfix on a VM=== We will now be installing the postfix application which will act as the Mail Transfer Agent (MTA) that will send and receive e-mail messages between servers (VMs as well as servers that are outside of our virtual network). '''Perform the following steps:''' #Switch to your '''VM2''' machine.#Check the status of the '''sendmail''' service by using the '''systemctl''' command. If the sendmail service is running, use the systemctl command to stop and disable that service. #Issue the following command to install the '''Postfix''' application (MTA):<br><br>'''yum install postfix'''<br><br>#What is the purpose of installing the postfix application in terms of using e-mail? Record your answer in your lab logbook.<br><br>'''NOTE:''' We need to configure the postfix application (i.e. our MTA) to recognize our recently-created domain name that we setup in lab3.<br><br>#Edit the Postfix configuration file: '''/etc/postfix/main.cf''' and edit this file to contain only the contents displayed below:<br><br>'''mydomain = senecaID.org'''<br>'''myorigin = $mydomain'''<br>'''mynetworks = 127.0.0.0/8, 192.168.X.0/24'''<br>'''relay_domains ='''<br>'''inet_interfaces=all'''<br><br>'''NOTE:''' Your MTA has the ability to resolve "fake" public address to an actual user account name. For example, if you have a user account called "msaul", you can have the MTA resolve the fake name "murray.saul" to the account name "msaul".<br>In order to do this you need to create an alias which is contained in the MTA's alias file.<br><br>#Edit the '''/etc/postfix/aliases''' file and add your first name as an alias to be resolved to your VM2's account name:<br><br>'''your-first-name''' &nbsp; &nbsp; &nbsp; '''your-vm2-regular-username'''<br><br>#In order to update the MTA's database for the newly-create alias, issue the following command:<br>'''postalias hash:/etc/aliases'''<br><br>#Finally, to start and enable your MTA, issue the following commands:<br><br>'''systemctl start postfix.service'''<br>'''systemctl enable postfix.service'''<br><br>#Check the '''/var/log/messages''' file to see that your MTA server started without error If there are any errors, correct them before continuing.  '''Record steps, commands, and your observations in INVESTIGATION 1 in your OPS335 lab log-book''' 

=== Reviewing the mail command =INVESTIGATION 2: INSTALL &amp; SETUP THE MAIL USER AGENT (MUA)==

===Install and configure Postfix on a VM===*On Vm 2 do the following:**Check the status of the sendmail service. If it show up as running or enabled, stop and disable it. **Install Postfix and mail yum install postfix mailx**While that is installing, you may wish to read Installing the mail manual page to remind yourself how it works.**Edit the Postfix configuration file, /etc/postfix/main.cf, and change the following parameters: mydomain = <senecaID>.org myorigin = $mydomain mynetworks Mail User Agent (MUA)= 127.0.0.0/8, 192.168.X.0/24 relay_domains = inet_interfaces=all

{{Admon/important|Warning|Make sure there are no other uncommented copies of these parameters in '''Perform the file.}}following Steps:'''

**Create #Issue the database file of mail aliasesfollowing command to install the '''mailx''' application (MUA):<br><br>'''yum install mailx'''<br><br> postalias hash#Refer to the chart below to acquaint yourself on how to use the mailx application:/etc/aliases

**Start and enable Postfix: systemctl start postfix.service systemctl enable postfix.service--- INSERT REFERENCE CHART ---

*We will now test to see if your MTA for your VM2 machine is correctly running by sending email messages to other servers (both within and outside your virtual network).  '''Perform the following steps:''' #Test email from your machine by sending an email to your Seneca account. using the following command:<br><br>'''mail -s "PART C3" <Your Seneca email address>Note: '''<Your Seneca email addressbr> is your Seneca email address.<br />Note'''NOTE: ''' after you type in your letter, enter a period in the first column on the last line and hit the ENTER key.<br><br>*#Check your learn email to see if you got the email (note that it may take a few minutes to arrive, so you may also wish to try an alternate email account if you have one). When you do receive that email make a note of the return address.*#If you did not receive the mail, check the mail logs on your machine to determine what the error is.*#Test email from the host your Host Machine by sending an email to your Seneca account. using the following command:<br><br>'''mail -s "PART C4" -r hacker@evil.com <Your Seneca email address>'''<br><br />Note: after you type in your letter, enter a period in the first column on the last line and hit the ENTER key.*#Check your Seneca email to see if you got the email. If you did make a note of the return address.*#Repeat the steps for INSTALL &amp; '''SETUP THE MAIL TRANSFER AGENT (MTA)'''Install and Configure Postfix on a vm' on ''INSTALL &amp; SETUP THE MAIL USER AGENT (MUA)''' for your VM 3'''VM3'''.

*If you were able to send e-mail to your Seneca e-mail account from your VM2 and VM3, then we should test to see if we can send email messages within our virtual private network.First, let's send a message using a static IP ADDRESS for each VM: '''Perform the following Steps:''' #Adjust your firewall (iptables) to allow traffic to port 25 on both VMs.**Also check # Check your '''/var/log/maillog ''' file to see the log entries that get created when mail is sent and received, and or notes when something goes wrong.*#Try sending an email from '''vm2 ''' to your '''vm3. ''' by issuing the command:<br><br>'''mail -s "PART E2" yyyyyy@[192.168.X.4]Note: yyyyyy is your Seneca ID'''<br><br />Note: the square brackets around the host IP address*#Try sending an email from your '''vm3 ''' to '''vm2. ''' by issuing the command:<br><br>'''mail -s "PART E3" root@[192.168.X.3] ''' <br><br>

Now try Let's complete this lab by sending email messages using our recently-created domain name: '''Perform the following Steps:''' #Use the '''host''' and '''hostname''' commands to confirm that each of your machines has the same ''hostname'' and that the DNS service verifies this to be true.#Restart your MTA (postfix) server if you changed the hostname on either mail server.#Try sending mail to yourself on both machines. For example, as the username <senecaID> on VM 3, use the command: <br><br>$ mail <senecaID>@vm2.<yourdomain>.org<br><br>'''NOTE:''' the machine will prompt for a subject: enter "testing" without the quotes.<br><br>#Enter the body of your e-mail message. When you have completed entering your email message, enter a period (.) in column 1 on the last line of your letter. This will send the signal: '''end-of-file''' and your letter will be mailed. You should end up back at the shell prompt. If you make a mistake, use '''CTRL-C''' to cancel the email (DO <u>NOT</u> USE CTRL-Z).#Use the '''mailq''' command on both machines (you will need to be root) to view the mail queue. Why would this command be useful for an administrator?#Use the mail command to check to see if you have received any mail.

*Now enter the body of your letter. When you're done''Record steps, commands, enter a period (.) and your observations in INVESTIGATION 2 in column 1 on the last line of your letter. This will signal endOPS335 lab log-of-file and your letter will be mailed. You should end up back at the $ prompt. If you mess up use CTRL-C to cancel the email, DO NOT USE CTRL-Z.book'''

==Completing the LabCOMPLETING THE LAB==

Exploration questions:==EXPLORATION QUESTIONS==