Enable Outgoing Mail on Raspberry Pi

This article explains how to send email from the Raspberry Pi. It is a generic procedure and also works on other Debian distributions. This is not for receiving mail, only for sending it. (Receiving email on the Pi is a much more involved process, requiring your Pi to preform the role of a full mail server).

The ability to send mail across the internet is useful. It enables your scripts and applications to send you email about system events or sending data such as pictures from a webcam.

I started with a fresh install of Raspbian, the image from June 2014, 2014-06-20-wheezy-raspbian.img to be precise. (UPDATE 7th April 2016: The procedure should also work with other releases and has been tested on Jessie). Download the image file, dd it to an SD card and boot your pi from that. Or just proceed using your current Pi installation.

Install Sendmail

This procedure uses sendmail, the great grandaddy of all email programmes. Install it now as follows. ssh into your pi, or sit in front of the desktop, as you prefer. Become root:

$ sudo su -

Update software lists and install:
# apt-get update
# apt-get install sendmail

This will install sendmail and a few other packages, create the directory /etc/mail, and perform a few other tasks.

Configure Sendmail

Change to /etc/mail and edit the file /etc/mail/submit.mc, using an editor of your choice. (Do not edit the submit.cf file)

# cd /etc/mail
# vi submit.mc

Add the three lines shown below in bold to the file. Put them just after the “DOMAIN(`debian-msp’)dnl” line, as shown:

VERSIONID(`$Id: submit.mc, v 8.14.4-4 2013-02-11 11:12:33 cowboy Exp $')
FEATURE(`authinfo',`hash -o /etc/mail/authinfo.db')dnl

Here, mail.btinternet.com is the mail server of my provider (BT). My domain name is bloggs.gotdns.org. Email sent from the Pi will appear to come from an email address “<user>@bloggs.gotdns.org“.

Save the submit.mc file after making the above changes.

Next, edit the authinfo file.

# vi authinfo

Make it contain a single line, like this one:
AuthInfo: "U:myusername@btinternet.com" "P:mypassword" "M:PLAIN"

myusername@btinternet.com is my email address at the ISP. mypassword is the password to go with it. Enter the appropriate address and password for you. Sendmail will use this information to authenticate with your ISP every time it sends an email. It is a basic spam prevention measure implemented by many service providers.

Save the authinfo file and use makemap to create the binary version. The following command creates a file called “authinfo.db“, using the information you placed into authinfo.

# makemap hash /etc/mail/authinfo < /etc/mail/authinfo

Finally, edit your /etc/hosts file and add your domain to the line containing “raspberrypi”. That is the same domain name you used in submit.mc, above (in my case, bloggs.gotdns.org). On a newly installed Raspbian Jessie, it looks like this:       raspberrypi

Change that to:       raspberrypi bloggs.gotdns.org

Now restart sendmail. This can take a couple of minutes sometimes, so be patient:
# service sendmail restart

Note:If you have found this page after encountering a message like “WARNING: local host name (raspberrypi) is not qualified; see cf/README: WHO AM I?, then adding the domain name to /etc/hosts as just described, should fix it.

Send a Test Email

Send a test email to a mail account you own, eg gmail, hotmail, outlook or whatever:
# /usr/lib/sendmail -v someuser@hotmail.com
Test from Pi

This will print a load of stuff as it sends the mail, including hopefully a “235 PLAIN authentication successful” message. Check your mail account to see the mail came through. (Check the “junk” mail folder too). It should not take more than a second or two, or maybe a few minutes at very busy times.

Fix Local Email

If the above test worked, Internet mail is working from your Pi. Great. Now, however, local mail fails. By “local mail”, I mean email sent from one user on the Pi to another user, for example when cron sends a user the output from their scheduled jobs, or when the system sends diagnostic messages to the root user. It may not be important to you, but best make it work anyway. Proceed as follows.

Tell sendmail not to authenticate for local mail. Edit the file /etc/mail/access and add this line:

SRV_Features: A

Save the file and type “make” to regenerate its binary version, access.db:

root@raspberrypi:/etc/mail# vi access
root@raspberrypi:/etc/mail# make
Creating /etc/mail/relay-domains
# Optional file...
Updating access_db ...
The following file(s) have changed:

** ** You should issue `/etc/init.d/sendmail reload` ** **

Restart sendmail:
# service sendmail restart

If you see messages complaining about “sasl2-bin” not being installed, and about enabling SASL2 support at a later date, they can be ignored for the purposes of this procedure.

As a test, try sending a local mail. Eg send a mail to the “pi” user.

root@raspberrypi:/etc/mail# /usr/lib/sendmail -v pi
Hello pi user from root

Again, lots of diagnostic stuff is printed, indicating successful delivery, including something like “050 … Sent”.

Check that user pi did indeed receive the mail. We could login as user pi and read the mail with an application (do that by all means), but just tailing the user’s mail file is quicker:

# tail /var/mail/pi

You will see the received mail, ie. lots of header information followed by a blank line and your actual message:

Hello pi user from root

Raspbian Wheezy only: Enable IPV6

At around the end of March 2016, an update was made to Raspbian Wheezy (Debian 7) that will prevent local mail from working unless you have IPv6 enabled. This only affects users of Wheezy. IPv6 is enabled by default on Jessie (Debian 8), so it isn’t a problem. However, Wheezy users might see errors like these after updating their systems with apt-get:

Eg. local mail fails, even after making all of the configurations above:

root@raspberrypi:# sendmail -v pi
pi... Connecting to [] via relay...
pi... Deferred: Connection refused by []

The “Connection refused” message indicates that the sendmail daemon is not running. Check it with:

root@raspberrypi:# ps -ef | grep sendmail

If it isn’t running, attempt to start the daemon:

root@raspberrypi:# service sendmail restart

If that falls (check with ps again), look at the end of the file /var/log/mail.log for messages like these:

# tail /var/log/maillog
root@raspberrypi:# tail /var/log/mail.log
Apr  3 14:52:07 raspberrypi sm-mta[3064]: NOQUEUE: SYSERR(root): opendaemonsocket: daemon MTA-v6: can't create server SMTP socket: Address family not supported by protocol
Apr  3 14:52:07 raspberrypi sm-mta[3064]: daemon MTA-v6: problem creating SMTP socket
Apr  3 14:52:07 raspberrypi sm-mta[3064]: NOQUEUE: SYSERR(root): opendaemonsocket: daemon MTA-v6: server SMTP socket wedged: exiting

The sendmail daemon is failing to start because it seems to require IPv6 to be running. After much messing about, I found the easiest solution was just to enable IPv6.

Edit the file /etc/modules

root@raspberrypi:# vi /etc/modules

and add a single line to the end of it:


and reboot the Pi:

root@raspberrypi:# shutdown -r 0

After the system reboots, local mail should be working and sendmail should be running correctly:

root@raspberrypi:# sendmail -v pi
root@raspberrypi:# ps -ef | grep send
root      2381     1  0 00:21 ?        00:00:00 sendmail: MTA: accepting connections 

Send a Picture

It is quite easy to send email attachments from the command line or a script. One of the best ways is to use mutt.

Install mutt:
# apt-get install mutt

Send an email. You don’t need to be root for this, so type <ctrl-d> to go back to the non-root user. The “echo” bit here just sends an empty email, and the “-a” attaches the jpg file. On my Pi, there is an image called “driveway.jpg” installed by default. Email it as follows. Note the double minus (–) seperating the destination adddress from the other options:

$ echo | mutt -a /usr/share/scratch/Media/Backgrounds/Outdoors/driveway.jpg -s "Photo" -- someuser@hotmail.com

I use this method to email webcam pictures to an external email account.


Thanks for reading. I hope you found this guide useful.

5 thoughts on “Enable Outgoing Mail on Raspberry Pi

  1. Just to confirm: it says create the file “authinfo” & then it mentions it in the config file as “authinfo.db” ~ is that correct?

    • Hi Riquez. Yes that is correct. authinfo.db is created when you run the “makemap” command. I’ve added an extra sentence to clarify that.

  2. Hi,

    Clearly this works, but I get 550 rejected is temporarily blocked. Contact support [pb1]
    Although from all other computers and devices, my mail works OK. Looks like maybe anything sent via simple command line sendmail has a suspicious looking header structure maybe?

  3. Hi, sorry to come back at you so long after you published this but I have been trying your method on a Pi running Jessie. I am also a btinternet user so I have set my system up almost the same as yours, just a different domain name which I get from No-IP.com.
    However, when I try to send an email I get the long list of text you mention but no sign of a “235 PLAIN authentication successful” message”. What I have noticed is part way through I get:
    Connecting to mx.bt.lon5.cpcloud.co.uk. via esmtp
    050 521 rgin14.bt.int.cpcloud.co.uk Service not available – no PTR record for

    Do you have any advice on what is causing this and how I might fix it? I’m not very experienced on Linux stuff so any suggestions would be gratefully received


    • Hi Philip. The mail system seems to be saying that there is no reverse DNS record (PTR record) associated with your No-IP domain name. That is, your domain name resolves to your IP, but in the other direction, your IP address does not resolve to anything. Usually, if you are using a dynamic IP address (which is most likely) your IP address should resolve to a temporary domain name allocated by your ISP. It can be checked with the “host” command.
      The command:
      …should print your IP address, and the command:

      …should print a temporary domain name

      do both commands work properly ?

      Cheers, Jim.

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