Configure Postfix to Use Gmail SMTP on Ubuntu

Question

I'm using this online guide here to enable simple mail sending from linux (ubuntu) terminal with postfix through some gmail account. I've done the steps listed there:

sudo apt-get install postfix mailutils libsasl2-2 ca-certificates libsasl2-modules
vim /etc/postfix/main.cf

And add these 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

Then edit this file:

vim /etc/postfix/sasl_passwd

To add the lines like it says in the guide:

[smtp.gmail.com]:587    [email protected]:PASSWORD

(Of course with my own mail and password) then finally:

sudo chmod 400 /etc/postfix/sasl_passwd
sudo postmap /etc/postfix/sasl_passwd

And then:

sudo /etc/init.d/postfix reload

When I try to send a simple mail nothing happens:

echo "Test mail from postfix" | mail -s "Test Postfix" [email protected]

(Of course here too with some other valid email)

What am I doing wrong? Thanks!

Answer 1

Issue may be related to application passwords. For example I can't use my gmail on old clients with my current password. You may want to create "Application Password".

Or Enabling less secure apps can help. (Most probably this is the solution)

For managing app paswords: https://myaccount.google.com/apppasswords

Extra info: Use Gmail as your SMTP Server – even when using 2-factor authentication (2-step verification)

Answer 2

I think you need validate certificates to avoid running into error.

Try with:

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

If you run into issues with above command, try rename the certificate to: thawte_Primary_Root_CA.pem in above command.

And now, reaload the server

sudo /etc/init.d/postfix reload