Mail server

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Running an Email Server

  • Mail Transport/Transfer Agents (MTAs) - send messages between servers (required)
  • Mail Delivery Agents (MDAs) - store messages in the recipient's mailbox (required)
  • Mail User Agents (MUA) - software for reading messages

You need a domain name and appropriate MX records in your DNS.


  • Linux: Email Services
  • Linux System Engineer: Mail Systems Using Postfix
  • Linux Foundation Cert Prep: Email Services (Ubuntu)

POP, IMAP and Exchange

POP works by contacting your email service and downloading all of your new messages from it. Once they are downloaded onto your PC or Mac, they are deleted from the email service.

IMAP allows you to access your email wherever you are, from any device. When you read an email message using IMAP, you aren't actually downloading or storing it on your computer; instead, you're reading it from the email service. As a result, you can check your email from different devices, anywhere in the world: your phone, a computer, a friend's computer.

Exchange offers the same syncing capabilities as IMAP, plus much more. Exchange is a Microsoft product, giving you the ability to still use Outlook as your email service and benefit from Exchange functionality.

Configure Postfix to use Gmail as a Mail Relay

How to Build an Email Server on Ubuntu Linux


Send from google emails on Ubuntu

Change your google account to use less secure authentication. Otherwise it won't work and you will receive an email with a subject "Critical security alert" after you try to send out an email.

sudo apt install mailutils
sudo nano /etc/postfix/   # no account information
sudo nano /etc/postfix/sasl_passwd # contains account information
cat /etc/ssl/certs/thawte_Primary_Root_CA.pem | sudo tee -a /etc/postfix/cacert.pem
sudo chown root:root /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
sudo chmod 0600 /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
sudo apt-get install --reinstall postfix
sudo /etc/init.d/postfix restart
sudo /etc/init.d/postfix reload
echo "Test Email message body" | mail -s "Email test subject" [email protected] # works

We can actually send to other email accounts. For example, we can use mailR package to send emails in R

send.mail(from = "[email protected]",
  to = c("[email protected]"),
  replyTo = c("[email protected]"),
  subject = "Test",
  body = "test",
  smtp = list( = "", port = 465, 
     = "yourname", passwd = "XX", ssl = TRUE),
  authenticate = TRUE,
  send = TRUE)

How to Send an Email with a Different “From” Address in Outlook

How to Send an Email with a Different “From” Address in Outlook. How Email Providers Handle Messages Sent From a Different “From” Address? How Do Scammers Use Fake “From” Addresses?

Bash Script to Send a Mail When ...

Bash Script to Send a Mail About New User Account Creation


Install WebMail Lite PHP based Webmail Client on Debian 9.1

Command line tools

6 Ways to Send Email from the Linux Command Line:

  • mail
  • mailx
  • mutt
  • mpack
  • sendmail
  • ssmtp


Mutt is a command line email app for Linux and here's how to set it up

sendemail package

sendEmail -f $USERNAME -s \
            -xu $USERNAME -xp $PASSWORD -t $USERNAME \
            -o tls=yes \
            -u "Web page changed" \
            -m "Visit it at $URL"

sendEmail -f [email protected] -t [email protected] \
            -s -xu [email protected] -xp YOURPASSWORD \
            -o tls=yes \
            -u "Hello from sendEmail" \
            -m "How are you? I'm testing sendEmail from the command line."


How to Set Up a Mail Server with Modoboa on Debian 10


Install and Configure Kolab Groupware on Ubuntu 16.04 LTS

Criptext: private email service


How to Install Zimbra Collaboration Suite 8.8 on Ubuntu

Temporary/Disposable email

Create A Temporary Email From The Command Line With tmpmail

Trouble shooting