What is SMTP?
SMTP stands for Simple Mail Transfer Protocol. First of all what is protocol? Almost all your online activity made through the help of protocols. Protocol is the set of roles and guidelines which is help your computer to link up to networks everywhere.
There are lot of protocols are there which are used for various purpose like send Email, File Transfer, Online shopping, read news etc. SMTP closely works with MTA (Mail Transfer Agent) which is running in your computer, so emails are moves from your computer's MTA to an another computer MTA.
How it works?
In simple words SMTP Server is a machine just like our normal server which is designed for more specific purpose. Our machine email client connect SMPT server using specific port (usually port number 25).
If we send the email through SMTP server, first our email client makes request to SMTP server which is configured in your machine.
SMTP server receive the request and verify your authentication credentials, once verification done then it is process further steps
The request contains message content, sender address, recipient email addresses and other information
Then the server send the request to recipient's mail server, recipient's server repeats the same process of authentication and verification.
Recipient's server verifies the sender and receiver addresses, message content, DNS issues, signature verification and more on.
Once everything fine, recipient mail server will deliver the message to recipient.
SMTP Providers:
There are several SMTP providers available across the world. I have listed few common service providers below.
PROVIDER
|
URL
|
SMTP SETTINGS
|
Gmail
|
Gmail.com
|
Smtp.gmail.com
|
Yahoo
|
Yahoo.com
|
Smtp.mail.yahoo.com
|
Outlook.com (former Hotmail)
|
Outlook.com
|
Smtp.live.com
|
Bluewin
|
Bluewin.ch
|
Smtpauths.bluewin.ch
|
BT Connect
|
Btconnect.com
|
Mail.btconnect.tom
|
Comcast
|
Comcast.net
|
Smtp.comcast.net
|
Earthlink
|
Earthlink.net
|
Smtpauth.earthlink.net
|
AOL
|
Aol.com
|
Smtp.aol.com
|
Orange
|
Orange.net
|
Smtp.orange.net
|
Tin
|
Tin.it
|
Mail.tin.it
|
Tiscali
|
Tiscali.co.uk
|
Smtp.tiscali.co.uk
|
Verizon
|
Verizon.net
|
Outgoing.verizon.net
|
Virgin
|
Virgin.net
|
Smtp.virgin.net
|
Wanadoo
|
Wanadoo.fr
|
Smtp.wanadoo.fr
|
AT&T
|
Att.net
|
Outbound.att.net
|
Configure SMTP server in apachi airflow:
Airflow is a python based platform for schedule and monitoring the workflows. Want to know more about airflow go through the airflow document.
Airflow allow us to send email notification when specific event occurs like job fails, retry, sla notification. It having email operator also you can send email based on your requirement. Before that we need to configure SMTP server for enable airflow can send email notification.
We need to add smtp configuration settings in airflow.cfg file which is usually located in airflow home folder (/root/airflow/). Here I have using gmail SMTP server for below example configuration.
Open airflow.cfg file in any editor and add configuration in [smtp] section.
[smtp]
# If you want airflow to send emails on retries, failure, and you want to use
# the airflow.utils.email.send_email_smtp function, you have to configure an smtp
# server here
smtp_host = smtp.gmail.com
smtp_starttls = True
smtp_ssl = False
smtp_user = <your gmail address>
smtp_port = 587
smtp_password = <password>
smtp_mail_from = <from mail address>
In default SMTP uses port 25, but if you using google SMTP server, you have to use port 587. Once done your configuration try using EmailOperator class in airflow to check the functionality.
send_mail = EmailOperator (
dag=dag_id,
task_id="simple_email_opearetor",
to=[''my_mail@gmail.com","second_mail@yahoo.com"],
subject="Testing",
html_content="<h3>Welcome to Airflow</h3>")
