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:
1 | aptitude install postfix sasl2-bin |
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.
1 | dpkg-reconfigure postfix |
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.
1 2 3 4 5 6 7 8 9 | mkdir /etc/postfix/ssl cd /etc/postfix/ssl/ openssl genrsa -des3 -rand /etc/hosts -out smtpd.key 1024 chmod 600 smtpd.key openssl req -new -key smtpd.key -out smtpd.csr openssl x509 -req -days 3650 -in smtpd.csr -signkey smtpd.key -out smtpd.crt openssl rsa -in smtpd.key -out smtpd.key.unencrypted mv -f smtpd.key.unencrypted smtpd.key openssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650 |
Finish configuring Postfix for TLS and SASL.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | postconf -e 'smtpd_sasl_local_domain =' postconf -e 'smtpd_sasl_auth_enable = yes' postconf -e 'smtpd_sasl_security_options = noanonymous' postconf -e 'broken_sasl_auth_clients = yes' postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination' postconf -e 'inet_interfaces = all' echo 'pwcheck_method: saslauthd' >> /etc/postfix/sasl/smtpd.conf echo 'mech_list: plain login' >> /etc/postfix/sasl/smtpd.conf postconf -e 'smtpd_tls_auth_only = no' postconf -e 'smtp_use_tls = yes' postconf -e 'smtpd_use_tls = yes' postconf -e 'smtp_tls_note_starttls_offer = yes' postconf -e 'smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key' postconf -e 'smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt' postconf -e 'smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem' postconf -e 'smtpd_tls_loglevel = 1' postconf -e 'smtpd_tls_received_header = yes' postconf -e 'smtpd_tls_session_cache_timeout = 3600s' postconf -e 'tls_random_source = dev:/dev/urandom' postconf -e 'myhostname = server1.example.com' postconf -e 'home_mailbox = Maildir/' postconf -e 'mailbox_command =' |
Finally, restart Postfix
1 | /etc/init.d/postfix restart |
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:
1 2 | START=yes OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd" |
Finish up SASL by creating the chroot directory, adding the postfix user to the sasl group, and then starting saslauthd.
1 2 3 4 | mkdir -p /var/spool/postfix/var/run/saslauthd dpkg-statoverride --add root sasl 710 /var/spool/postfix/var/run/saslauthd adduser postfix sasl /etc/init.d/saslauthd start |
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.
1 | telnet localhost 25 |
After establsihing a connection with the Postfix service, run:
1 | ehlo localhost |
You should see a few lines of output. Make sure that the two most important lines are there:
1 2 3 4 | . . . 250-STARTTLS 250-AUTH PLAIN LOGIN . . . |
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.
1 2 3 | aptitude install dovecot-imapd dovecot-pop3d perl -pi -e 's/#mail_location =/mail_location = maildir:\/home\/\%u\/Maildir/' /etc/dovecot/dovecot.conf /etc/init.d/dovecot restart |
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:
1 2 3 | wget http://www.dovecot.org/tools/courier-dovecot-migrate.pl chmod 755 courier-dovecot-migrate.pl ./courier-dovecot-migrate.pl --to-dovecot --recursive /home |
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.
1 | ./courier-dovecot-migrate.pl --to-dovecot --convert --recursive /home |
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.
1 2 3 4 | namespace private { prefix = INBOX. inbox = yes } |
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:
1 | Mar 27 00:36:56 swift postfix/smtpd[12537]: warning: SASL authentication failure: cannot connect to saslauthd server: No such file or directory |
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.
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when I try to run this command “perl -pi -e ’s/#mail_location =/mail_location = maildir:/home/%u/Maildir/’ /etc/dovecot/dovecot.conf”, I got an error and can not proceed.
Here is the details:
syntax error at -e line 1, near “s/#mail_location =/ mail_location = maildir:/home”
Execution of -e aborted due to compilation errors.
Can you give me some suggestions?
BTW, ignoring the errors above, I can use evaluation to send and receive the email from my configured server, but when I try to use Outlook Express in Windows, I can only send out email but can not receive one, the OE always prompt me about the password. What’s the problem in this case?
Thanks!
David, Looks like I forgot to escape the forward slashes. Try this:
and then restart Dovecot.
yes! It is okay now!
Enh…., but using OE is still a problem in receiving an email
The behavior of continually asking for the password seems to indicate that a connection is being made. I would head to the server logs which should indicate why the authorization is being rejected.
Is this configuration supported / easily set up on 64-bit hardware and Ubuntu OS?
Daniel, yes. In fact I wrote the guide walking through my x86_64 Ubuntu install. I would imagine that the Ubuntu setup and configuration would be the same for both 32 and 64-bit.
Hi, thanks for a great tut.
Where you said the stuff about setting it up with your root FQDN and server1.example.com (server FQDN), what if my slicehost server is simply mywebsite.org? I don’t have any subdomain for it. Would I set mywebsite.org in both cases, or did you mean for me to setup something like mywebsite.org as root and mail.mywebsite.org as the system mail name?
Sam, you would use something like mail.mywebsite.org. For example, the hostname of the server running this blog is “bamboo” so I use the FQDN (bamboo.jonsview.com) in the Postfix configuration. Also keep in mind that the address used for email should match the reverse DNS and MX records, both of which use the same FQDN.
Another little side tip: the hostname should not match any domain that is intended for use on the server. For example, if you wanted to use user@example.org, then the hostname should not be example.org but something unique such as server1.example.org.
Ok, I set it up using mail.mywebsite.org (my website being http://www.mywebsite.org in this example).
I wanted to do all of this so I could use mail on my phpbb forum hosted on my dedicated server. Basically mail wasn’t working (user authenticating emails and such). I’m not quite sure what settings to use now, though. I’ve set it up to work through the local smtp server, however there are 3 boxes I’m unsure what to put in.
Authentication method for SMTP – options are PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, POP-BEFORE-SMTP – “Only used if a username/password is set, ask your provider if you are unsure which method to use.”
SMTP username – “Only enter a username if your SMTP server requires it.”
SMTP password – “Only enter a password if your SMTP server requires it.”
Considering I did my install pretty much EXACTLY as you wrote above (with the exception of my own passkey in the ssl directory), what do you think my settings may be?
Nevermind! Figured it out!
Excellent! Glad to hear that you got it working.
Jon:
I think that you saved me from institutionalization. Thank you very much for your help. If you need to learn how hard to push the power switch on a Pavilion, let me know: I (modestly) consider myself somewhat of an expert.
blue
Is there any special way to add users to the email system? Aside of sudo useradd name?
olboy, yes, virtual user/boxes are possible. It’s been years since I’ve used them (and on a Exim setup), but Dovecot appears to have a similar capability. Here’s the link: http://wiki.dovecot.org/VirtualUsers.
Well this works nicely, except for SSL on SMTP.
Is there any way to enable this?
Thanks for a great guide!
Sorry, TLS is what I wanted.
Seems that my virus-scanner doesnt support TLS, so i disabled scanning of outgoing messages.
Everything works now!! wee
I just wondering where i can get ehlo tool coz I using ubuntu 9.04 server and istalled postfix separate or whats included in ubuntu package no socha thing as EHLO..
ok never mind about ehlo i just discover another problem after
./courier-dovecot-migrate.pl –to-dovecot –recursive /home
i’ve got error No maildirs found
i justed fixed perl version.
thx
rossi,
If you’re migrating from courier be sure to read the wiki for the latest information: http://wiki.dovecot.org/Migration/Courier.
You only need to follow the instructions in Appendix A if you’re migrating from an existing setup. If this truly is the case, one possibility is that your courier configuration is using the older mailbox format rather than Maildir, but that migration is outside the scope of this article.
is it any mail server program which would be easy to setup i mean without these mile long config files, some nice gui just add FQDNs, IP, users/passwd some mail dir quota, something loke that.
GMail, MobileMe? You could always splurge for a control panel that will assist with some of this, but mile long config files are just a typical day in the life of a Linux systems administrator… Have you considered a managed service from someone like MediaTemple?
Hi,
im a newbie.. using linux for the past three months.. currently working with django-postgresql application..
i followed all the steps given by u, to set up email server in my machine. im using ubuntu9.04.. when i give ” telnet localhost 25 ” it shows me like this,
Trying ::1…
Trying ::1…
Trying 127.0.0.1…
Connected to localhost.
Escape character is ‘^]’.
Connection closed by foreign host.
what could be the problem?
Problem with SASL
See this link!!
http://www.vivaolinux.com.br/dica/Smtp-autenticado-erro-SASL/
I have no words to say thank you, you has done a great job, may God bless you, hugs from Cuba