How To: Setup Email Services on Ubuntu Using Postfix (TLS+SASL) and Dovecot

Here is a guide on getting Email services running on Ubuntu Intrepid. I used Postfix for core services (SMTP wtih TLS and SASL) and Dovecot for fast IMAP and POP3. This tutorial has been tested on a bare bones Ubuntu 8.10 slice from Slicehost.

Preamble

Estimated Time Required: 10-15 minutes

This guide makes several assumptions. For example, it assumes that you will use Maildir. If you decide to make any changes, just keep an eye out for any subsequent changes that might be needed down the line. If you are upgrading from another system, such as Courier, please look at Appendix A.

If you prefer Postfix and Courier, refer to my older tutorial which is reported to work with Ubuntu Intrepid.

Postfix

Let’s get core email functionality going with Postfix:

You will be asked a few questions with a nice graphical interface. Here are the answers for some of them. Replace all occurrences of example.com with your root FQDN (e.g. jonsview.com), and server1.example.com with your server’s FQDN (e.g. swift.jonsview.com).

  • General type of mail configuration? Internet Site
  • System mail name? server1.example.com

Unfortunately, the graphical configuration interface that was automatically launched was a condensed version. You will need to run the full graphical configuration utility.

Again, you will be asked some questions:

  • General type of mail configuration? Internet Site
  • System mail name? server1.example.com
  • Root and postmaster mail recipient? Leave blank
  • Other destinations to accept mail for? server1.example.com, example.com, localhost.example.com, localhost
  • Force synchronous updates on mail queue? No
  • Local networks? Leave default (127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128)
  • Mailbox size limit (bytes)? 0
  • Local address extension character? Leave default (+)
  • Internet protocols to use? ipv4 (most likely)

Next, let’s take care of certificates for TLS. You will be asked several questions during this process. Fill them in as you see fit.

Finish configuring Postfix for TLS and SASL.

Finally, restart Postfix

SASL

Authentication will be done by saslauthd which will need to be configured to support a chrooted Postfix setup. Edit /etc/default/saslauthd and add or change the following settings so that they match:

Finish up SASL by creating the chroot directory, adding the postfix user to the sasl group, and then starting saslauthd.

Testing

At this point, core email services should be up and running. Let’s make sure that you’re in good shape before moving on. First, establish a connection with the mail server.

After establsihing a connection with the Postfix service, run:

You should see a few lines of output. Make sure that the two most important lines are there:

Type quit to get out.

Dovecot

Note: If you followed my last guide and are migrating from Courier, please see Appendix A before continuing.

Install and configure Dovecot.

If everything went smoothly you should now be in email nirvana. Each user has their own email account and you can move on to virtual accounts if you desire.

Appendix A: Courier to Dovecot Conversion

Please refer to this Dovecot wiki article for detailed information, but in a nutshell:

If everything looks good, then perform the actual conversion.

Note: Even if 0 mailbox changes are shown, the script may still be working. If there aren’t any explicit errors, run the conversion and then check the Maildirs for dovecot indexes.

For a transparent conversion you will need to setup Dovecot to use INBOX as the namespace for private mailboxes. Edit /etc/dovecot/dovecot.conf and uncomment the namespace private { block (and corresponding } ). Uncomment #prefix = and change to prefix = INBOX. (include the period). Finally, change #inbox = no to inbox = yes. In essence, it should look like the following, which has been stripped of comments for brevity.

Appendix B: SMTP Troubleshooting

If core email services and IMAP are working, but not SMTP, then it’s most likely that sasl is not set up properly. Log entries like the following in /var/log/mail.warn will confirm this:

Last words

I’ve always found setting up email services on Linux a pain, so hopefully this has helped you get up and running. Please let me know if you find any errors, or have suggestions that would make this guide easier to understand.

81 thoughts on “How To: Setup Email Services on Ubuntu Using Postfix (TLS+SASL) and Dovecot

  1. Thank you so much for this tutorial!

    I’ve got both an an MTA and a MDA running perfectly, using secure ports on my LAN and later on WAN. 🙂

    I was able to use port 993 (secure IMAP) right from the start.

    For secure smtp (port 465), I’ve only commented out a few lines in /etc/postfix/master.cf

    “netsmtps inet n – – – – smtpd” and the next five lines which begin with “-o”

    I also noticed in my logs this message:

    “dovecot: config: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:19: namespace private {} has been replaced by namespace { type=private },

    so I changed

    namespace private { prefix = INBOX. inbox = yes }

    to

    namespace { type = private prefix = INBOX. inbox = yes }

    I am not an expert in code syntax, but after this change the errors stopped, so I assumed that everything is fine now.

    Thank you again!

  2. Dear Mr. Stacy,

    Thanks you ever so much for the priceless tutorial. I have followed about 6 to my count up to now, and yours was the only one that gave me a fully functional internal and external email server.

    A few messages between my gmail and my email server confirmed it. Thank you again, you really make the days of people like us.

  3. Just a note for everyone, I just upgraded to Ubuntu 12.10 and this same setup continues to work just fine for me. The only change that I noticed was an additional question asked while running the dpkg-reconfigure postfix command.

    If you’re asked “Use procmail for local delivery?” answer “Yes”.

    If you have a spam problem you might also check out: http://townx.org/blog/elliot/simple_spamassassin_setup_with_postfix_and_dovecot_on_ubuntu_breezy

  4. Thanks so much for this, it works (Ubuntu 12.04)

    Do you have any good tutorial for setting up virtual users (non-linux accounts) with Dovecot, that works with your tutorial above?

    I’ve been trying for a week now, nothing I found works (sending to a virtual user fails with “no such user here, all the time).

    Thanks again!

  5. Dear Sir,

    Thank you for your tutorial . I am getting some problem with “Edit /etc/default/saslauthd” I cannot find any file called “saslauthd”. I am very new to linux it would be very helpful if you kindly explain.

    Thanking you, Ehsan

    1. The guide was written for an older version of Ubuntu, so it’s possible that some things have shifted around. First, make sure that saslauthd (sasl2-bin) is actually installed. If the config file still isn’t there, then it’s possible that it’s moved to a new location, although I haven’t seen any references on the web for this to be the case.

  6. Great tutorial; very straightforward (it really only took 10 minutes!).

    I can confirm that this works “as is” for Ubuntu 8.04.

    Thanks for posting!

  7. thanks jon, finally my mail server is working, try to find the answer on how should we make configuration in postfix main.cf but not find the right answer to me, until I come to your pages. thanks. wawan

  8. This is awefully good. I have been reading all those instructions and none of them are as easy and as good as this one.

    Thanks buddy. !!

  9. So not that I’ve completed this tutorial, how do I proceed from here? How do I add usernames and passwords for individuals who want to use my email services? How do I know that the email works? Just a few questions I have other than that thanks for the great tutorial I found that the only errors I made were my fault not the tutorials 😀

  10. I too am having trouble with the line, “/etc/init.d/saslauthd start” I get the following – /etc/default/saslauthd: 55: Syntax error: Unterminated quoted string

    I’ve made sure sasl2-bin is installed. I’ve checked for any updates. and I’ve restarted.

    Does anyone have any suggestions. I’d really love to get this working. Many thanks

    1. Sounds like the config fille is corrupt. Perhaps a copy/paste error, the configuration format has changed since I wrote the tutorial, or any other number of reasons. Try to see what’s going on in line 55 of the file to correct the problem by adding the missing quote terminator. Another option is to purge the sasl2-bin and configuration with the package manager and try again.

  11. /etc/init.d/saslauthd start — This line is failing for me.. saying saslauthd not found.

    Also, i tried sending email to my gmail id after this and it did not work. I did not receive any email. Any suggestions.

  12. This is a nice info. It saved my time a lot to build a mail server. Just to share my experience, getting “authentication” issue for pop, I found that, similar to your tip of “telnet localhost 25”, I run “telnet localhost 110” on the server to check how the authentication had been, and I could resolve it later. Thanks much for this great article !

  13. THANK YOU!!!

    I wish I’d found this 15 tutorials earlier. It’s the only one that has worked 100% without any swearing!

  14. Hey,

    I think installation went well following your steps. Just one question though. When I ran ‘telnet localhost pop3’ at the terminal, I get the return “+OK Dovecot ready,” but it doesn’t give me the login prompt. How can I check my mails then?

    ice

    1. The purpose of telnet in this guide was simply to test. As for actually retrieving email, you will have to install an email client such as mutt, or download the email with an imap or pop3 client to your local computer, or install a webmail application such as Squirrelmail.

    2. See an example below;

      root@userver1:/etc# telnet localhost 110 Trying ::1… Trying 127.0.0.1… Connected to localhost. Escape character is ‘^]’. +OK Dovecot ready. user mii +OK pass mii +OK Logged in. list +OK 1 messages: 1 720 . retr 1 +OK 720 octets

  15. Hey Jon,

    I messed up. For system mail name, I typed in server1.example.com. I don’t have my own website. Should I have written localhost? I want to be able to localmail myself. I’m just learning to build a contact form with php. Should I change system mail name to localhost? Or leave it blank? In either case, how can I amend system mail name? Thanks.

    1. ice, this guide and setup are extreme overkill if you only need to send emails. If that’s the case you only need a simple MTA such as postfix. It won’t allow you to deliver mail locally, but you can deliver to another valid email address (e.g. a gmail account) and will save yourself a lot of unnecessary headaches.

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