How to install and configure Postfix smtp relay using Gmail on ubuntu 16.04 | 18.04 | 20.04 - TechBeginner

Welcome to TechBeginner.in, Tech Beginner provides technical blog for Online Linux Tutorials, Ubuntu Tutorials, Redhat Tutorials and CentOS 7, Configuration of server like Web Server, Application server, Database server, Window server, networking, html, css, java script, php, wordpress, opencart, magento, joomla and etc.

How to install and configure Postfix smtp relay using Gmail on ubuntu 16.04 | 18.04 | 20.04

Share This

Postfix is an Mail Transfer Agent , Its is very powerful and easy to configure email server, On this post we will install and configure smtp relay using Gmail.

To configure Postfix as a relay smtp server using Gmail, You must have a Gmail email id and password as well as You have allow less-secure in your gmail account to allow postfix to use the gmail credentials.

Updating hostname

Step 1:- To install all required dependencies by following commands with root privileges, You must set your machine hostname like mail.example.com

sudo -i

hostnamectl set-hostname mail.example.com


Now you need to reboot the ubuntu machine to get effects on machine hostname.

Installation dependencies and Postfix packages.

Step 2:- After this we can performed the required packages.

apt-get install postfix  libsasl2-2 mailutils ca-certificates libsasl2-modules -y


Note :- While installing Postfix, You wiil be asked for hostname name you need enter your mail.example.com after configuration of your FQDN within postfix, We are ready to configure smmtp relay with Gmail credentials.

Step 3:- After this We need to specified our Gmail username and password by following the commands.

vim /etc/postfix/sasl_passwd


You need to replace your username and password in the file

[smtp.gmail.com]:587    USERNAME@gmail.com:PASSWORD


Save and exit from the editor.

Postfix configuration

Step 4:- In next step, You need to open the postfix mail config with by using following commands.

vim /etc/postfix/main.cf


Add the following the lines.

relayhost = [smtp.gmail.com]:587


smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_use_tls = yes



Save and exit from your editor.

Update the permission

Step 5:- Now you need to update the permission of sasl_passwd file:

chmod 400 /etc/postfix/sasl_passwd

postmap /etc/postfix/sasl_passwd


Step 6:- After this you need to verify the certificate certificates by following the commands.

cat /etc/ssl/certs/thawte_Primary_Root_CA.pem | sudo tee -a /etc/postfix/cacert.pem


You should get output like this :-



-----BEGIN CERTIFICATE-----

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-----END CERTIFICATE-----

 

In  case you did not get ant signature of the certificate so then you need to use

to Thawte_Premium_Server_CA.pem 

Restart the Postfix service

Step 7:- After getting certificate signature details all thing is going good, Now the time has come to restart the postfix the services to get effects.

systemctl restart postfix


Testing Postfix 

Step 8:- After this we need to test the postfix is working or not, To do that you need to You need to use the given commands to sent a test email to your email address to verify its proper working or not.

echo "Postfix email from smtp relay server" | mail -s "Testing Postfix" username@example.com


Note :- If you want to use postfix smtp relay in your monitoring tools like Nagios you have postfix commands, To get your mail command path by using the following cli.

which mail


You should get output like this - /usr/bin/mail this is use in your Nagios SMTP configuration with Postfix.

No comments:

Post a Comment