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Online References:
* [https://help.ubuntu.com/community/Dovecot Dovecot Community Documentation]* [https://www.debian-administration.org/article/275/Setting_up_an_IMAP_server_with_dovecot Setting up an IMAP Server with Dovecot]
This week, we will set up a '''Postfix''' demonstration for <u>receiving</u> email on your '''VM3''' machine.
In this lab, we will begin by using the existing '''Postfix''' service on your '''VM3''' machine, then add an Local Delivery Agent ('''LDA''') by installing the '''dovecot-lda''' package on VM3, configure it, and test it to make sure that is is working correctly.
Finally, we will set up an '''IMAP''' server (Dovecot) on VM3, so you can read your email from an MUA such as ''Thunderbird'' or a ''Webmail'' (we will set up a webmail application in a later lab).
{{Admon/important |Set up MX Record in your DNS Server|If you haven't already done it - set up an '''MX ''' record in your DNS server to make '''vm3.yoursenecaid.org ''' the server responsible for receiving emails for anyuser@yoursenecaid.org ('''vm3 ''' will be used for <u>receiving</u>, '''vm2 ''' for <u>sending </u> only).}}
=== Assigning Responsibility =INVESTIGATION: SETTING UP MTA FOR RECEIVING EMAIL ==
The other thing an SMTP server can be configured to do is receive email. Your SMTP server, in this case, forwards the received mail message to <u>another</u> SMTP server, which in turn, forwards it to the Local Delivery Agent (LDA). This is done using postfix by setting the '''mydestination''' parameter (configuration variable) to include '''$mydomain''' (this is assuming you've set up '''mydomain''', '''myorigin''' , and '''inet_interfaces''' the same way as in the previous lab). Perform the following steps on VM 3: #Edit your the '''/etc/postfix/main.cf ''' file and scroll .#Scroll down to (or search for) the line containing: '''mydestination'''. Set it up and change line to look like thisthe text shown below:
<pre>mydestination = $mydomain, $myhostname, localhost.$mydomain, localhost</pre>
#Dovecot is not installed when you installed your Virtual machines in previous labs.#Install the Dovecot application by issuing the following command:<br>yum install dovecot#Edit your /etc/postfix/main.cf file and scroll down to (or search for) '''mailbox_command'''. Add the following line:
<pre>mailbox_command = /usr/libexec/dovecot/dovecot-lda -f "$SENDER" -a "$RECIPIENT"</pre>
<ol><li value="4">Finally, edit the '''/etc/dovecot/conf.d/10-mail.conf ''' file and set indicated where you want your mail delivered:by including the following line</li></ol>
<pre>mail_location = maildir:~/Maildir</pre>
=== Test Sending a Mail Message from VM2 (Using Thunderbird)===
<ol><li value="2">Create a new account on your '''vm3''' machine using only your <u>first</u> name. We still haven't set up IMAP (for reading email) but we can will use this account as a one-time "test that " if the mail message has been received on your VM3 machine (from your VM2 machine).<br><br>'''Note:''' It is being delivered. Use the new <u>'''important'''</u> that you '''<u>don't</u>''' create this same account in Thunderbird name on your vm2 machine, since you want to send an email to firstname@yoursenecaideasily identify the difference between the sending and receiving SMTP servers.org and then check the contents of /home/firstname/Maildir<br><br></newli></ on vm3. - there should be a file there with the contents of your email.ol>
<ol><li value="3">We still haven't set up IMAP (for reading email) but we can test that the message is being delivered. Use the new account in Thunderbird to send an email to '''firstname@yoursenecaid.org''' and then check the contents of '''/home/firstname/Maildir/new/''' on your '''vm3''' machine. There should be a file there with the contents of your email.</li><li>If there isn't one - is no file, then check the log file '''/var/log/maillog ''' to see what went wrong.</li><li>If you can see a file in the '''/home/firstname/Maildir/new/''' directory, then review the procedures on how you got the email server working (since you have performed many steps and set up many services).</li><li>Refer to the diagram at the top of this lab. Which services have you currently set up? Record your findings in your lab Logbook.</li></ol>
{{Admon/important |Encountering error messages when sending email|If you got it cannot properly receive sent e- this is a good time to stop and ponder how it all workedmail messages, check the '''/var/log/syslog''' file for errors. You<br><br> If you locate an error message in that file such as: 've gone through setting up a lot of services''Fatal: Error reading configuration: Invalid settings. Look at ..''', then add the diagram following <u>parameter</u> in '''/etc/dovecot/dovecot.conf''':<br>'''postmaster_address at the top of the page - which services DOMAIN''' (where DOMAIN is actually <u>your</u> domain).<br><br>After you have you set up?saved those changes, then '''restart''' your dovecot service.}}
== Reading Email via = Viewing Received Mail Message on VM3 VIA IMAP (Using Thunderbird) ===
Finally , we'll will set up the IMAP server so we can read email. The current way we've set it up - have configured our mail server on our VM3 machine should allow all the email for anyaccount@yoursenecaid.org should end up on be delivered to our '''vm3''' machine. We will set up Dovecot (with IMAP, IMAPS in a later the next lab) to get easy access to that email.
#The configuration file for the Dovecot service (which is not the same thing as dovecot-lda) is: '''/etc/dovecot/dovecot.conf'''. Modify the '''protocols''' option so that Dovecot will work with IMAP connections, no POP3 or LMTP.# Start the dovecot service, and ensure it will always start automatically when the machine boots.# Use the '''netstat''' command to confirm the service is listening, and use telnet on the host to confirm you can connect to it.#If you can connect - it's now time to do something wrong, that is connect to our IMAP server using Thunderbird over an unencrypted connection.# Edit the '''/etc/dovecot/conf.d/10-auth.conf''' file and set '''disable_plaintext_auth''' to '''no'''.# Then edit the '''/etc/dovecot/conf.d/10-ssl.conf''' file and set '''ssl''' to '''yes'''.<br><br>'''Note:''' This combination of parameters will allow your username and password to be sent over the internet in plain text, for anyone interested to look at. In the following lab we'll set up secure SMTP and IMAP connections, for now this is all we have time for.<br><br># Restart dovecot so the changes take effect.#Try to connect to your IMAP server with Thunderbird by clicking on your '''Inbox'''.#If nothing happens, then check the Thunderbird Activity Manager for any errors. If the connection is successful, you should see the '''Trash''' box <u>appear</u> below Inbox.# Finally, send an email message from '''yoursenecaid@yoursenecaid.org''' to '''yoursenecaid@yoursenecaid.org''' using the Thunderbird application. The mail message should be sent without errors, and you should notice a '''Sent''' folder appear in the list. If all worked well, you should see your message arrive in the '''Inbox''' and you know that your configuration works correctly.
Students should be prepared with '''all required commands (system information) displayed in a terminal (or multiple terminals) prior to calling the instructor for signoff'''.
::<span style="color:green;font-size:1.5em;">✓</span>Thunderbird server configuration for your account.
::<span style="color:green;font-size:1.5em;">✓</span>Logs on vm2 and vm3 showing the message has been sent and received.
==EXPLORATION QUESTIONS==
# What is the purpose of the '''Dovecot''' package?
# What is the purpose of the '''mydestination''' parameter contained in the '''/etc/postfix/main.cf''' file?
# Why are '''IMAP''' and '''POP''' email servers placed on separate machines (vms)?
# What is the purpose of the '''mail_location''' parameter contained in the '''/etc/dovecot/conf.d/10-mail.conf''' file?