Changes

* [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]

We will begin by using the existing Postfix service You may ask yourself, ''"why not install on your VM3 VM2 machine, then add an Local Delivery Agent ('''LDA''') by installing since we used the VM2 machine in the previous lab?"'''dovecot-lda''' package, configure it, and test ti to make sure that is is working correctly.

FinallyThe reason for this (described in the previous lab) was that you will be able to send email out of your network, and receive email from within your network, we but you will set up an '''IMAP<u>not</u>''' receive email from outside of your network due to the following reasons::* Individuals outside of your domain will never find the MX records because there are no '''.org''' servers pointing to your DNS server (Dovecoti.e. you haven't paid for it) so you can .:* Even if the individuals could read your email MX records, your local network is using IP addresses on a '''private subnet''', which is not routeable on the Internet, so it cannot be reached from an MUA such as Thunderbird or a Webmail (we will set up a webmail application in a later lab)outside of your system.

{{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 default job of an SMTP server is === Specifying Which Domains are Used to forward Delivered the message recieved to another email server. That's what we've set up in the previous lab: your postfix receives an email from your client (Thunderbird) and forwards it to the destination SMTP server. The other thing an SMTP server can be configured to do is receive email. It still uses SMTP but instead of forwarding it to another SMTP server it will forward it to the Local Delivery Agent (LDA)."Received" Mail Messages===

With postfix this is done by setting the The default job of an '''mydestinationSMTP''' configuration variable server is to include '''$mydomain''' forward the message received to another email server. We performed that step in the previous lab: in other words, your postfix MTA receives an email from your MUA (this is assuming you've set up '''mydomain''', '''myorigin''' , Thunderbird) and forwards it to the destination '''inet_interfacesSMTP''' the same way as in the previous lab)server.

 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:

Now even :'''Note:''' Even though your machine's name is ''vm2.yoursenecaid.org - '', your postfix MTA will also receive emails for addressed to the domain called: yoursenecaid.org === Installing and Configuring the Local Delivery Agent (LDA) ===

=== Postfix is capable of performing the function of an LDA ===, but its LDA capabilities are limited, thus postfix is generally not used for that purpose. Currently, the most popular LDA is ''LMTP'', but we will be installing, configuring, and using an LDA called '''Dovecot''' since it is also popular and we will later be setting up Dovecot as an '''IMAP''' server. Using both Postfix and Dovecot will actually increase the performance of our IMAP server.

Postfix is capable of performing the function of an LDA but it has limited configurability, and is generally not used for that purpose. Currently '''Perform the most popular LDA is LMTP but wefollowing steps:'ll use dovecot-lda because it's also pretty popular and we'll later be setting up Dovecot as an IMAP server. Using the two as a pair will increase the performance of your IMAP server.

#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:

Don:NOTE: Do <u>'t ''not'''</u> replace any variables, those are set automatically by Postfix when it runs the LDA. If you're are interested - in learning more about the Dovecot application, you can read about dovecot-lda [http://wiki.dovecot.org/LDA/Postfix here] and [http://wiki.dovecot.org/LDA here] but it's not required reading(i. If you look - you'll see that dovecot-lda doesn't exist yete. Install the dovecot package - that will come with dovecot-ldaoptional reading for interest only).

<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>

Don't forget to restart <ol><li value="5">Restart your postfix service. dovecot-lda is just a program invoked by Postfix, it doesn't have an associated service.</li></ol>

=== Test Sending a Mail Message from VM2 (Using Thunderbird)===

First use netstat {{Admon/important |Sent messages will not be saved to the sent folder|During this step the messages you send will not be saved to the sent folder and telnet to confirm your service Thunderbird will permanently hang with a message that it is listening on saving the correct ports/interfacesmessage. You It will probably never succeed, as we have not yet configured the imap server to open accept the appropriate firewall port on vm3 connection necessary for that to allow incoming SMTP connectionswork.}}

If all worked so far - you should be able to send email to any regular user on vm3 using '''Perform the email address yourusername@yoursenecaid.org using Thunderbird on vm2.following steps:'''

Create a new account #Use the '''netstat''' and '''telnet''' commands (like you did in lab 4b) to confirm your service is listening on the correct ports/interfaces. You will probably have to open the appropriate firewall port on '''vm3 using only your first name''' to allow incoming '''SMTP''' connections. We<br><br>'ll use this one time for testing receiving ''Note:''' You should be able to send email to any regular user <u>on</u> '''vm3''' using the emailaddress '''yourusername@yoursenecaid. Itorg''s rather important that you don't create this using the Thunderbird application on your host machine (which is configured to use the account on your vm2 - so that you continue to see the difference between the sending and receiving SMTP servers).<br><br>

<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 '''Perform the Dovecot service (which is not the same thing as dovecot-lda) is /etc/dovecot/dovecot.conffollowing steps:'''

#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.

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 /etc/dovecot/conf.d/10-auth.conf and set '''disable_plaintext_auth''' to '''no'''. Then edit /etc/dovecot/conf.d/10-ssl.conf Record steps, commands, and set '''ssl''' to '''yes'''. This combination of parameters will allow your username and password to be sent over the internet observations in this INVESTIGATION in plain text, for anyone interested to look at. In the following your OPS335 lab welog-book'''ll set up secure SMTP and IMAP connections, for now this is all we have time for.

Finally - send an email from yoursenecaid@yoursenecaid.org to yoursenecaid@yoursenecaid.org using Thunderbird. The message should go out without errors, you should see a Sent folder appear in the list, and you should see your message arrive in the inbox. If all that happend - your setup is correct. = Completing the Lab = COMPLETING THE LAB ==