We need to install exim4 to enable outgoing email

# apt-get install -y exim4

# dpkg-reconfigure exim4-config

Configure mail as appropriate for your site and IT infrastructure. We outline a sample standalone configuration below. The requirement is for php to be able to send mail (registration confirmation and other notices need to go out) and for exim4 to receive mail (for support ticket and forum email gateway functions to work).

This is just an example of a standalone mail configuration.

General type of mail configuration

internet site; mail is sent and received directly using SMTP

Mail name

enter the fully qualified domain name (FQDN) of the host (example.com)

IP-addresses to listen on for incoming SMTP connections

leave blank (listen for connections on all available network interfaces)

Other destinations for which mail is accepted

leave blank or (equivalently) with local hostname (all local domains will be treated identically)

Domains to relay mail for

leave blank

Machines to relay mail for

leave blank

Keep number of DNS-queries minimal (Dial-on-Demand)

No

Delivery method for local mail

mbox format in /var/mail/

Split configuration into small files?

Yes

Use a real email address below so you can see if you get the email

# Mail -v someone@gmail.com

NOTE: After being prompted for a subject and pressing return, the Mail app will read the body of your email. Just type a test message and press return after each line. Once you are done with your email's body, enter a single '.' on it's own line and press return. The mail program will stop reading your input and will print a bunch of low level SMTP connection info to the screen as it delievers your message. At the bottom you should see a "Completed" line. You might have to press return after the "Completed" message to return to a command prompt.