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Configure sending mail via sSMTP on Linux
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Configure sending mail via sSMTP on Linux

For your information

These are instructions for setting up mailings through the Selectel mail service using the sSMTP utility on a Linux server.

  1. Make sure that you have connected the mail service for the domain and the domain has received the Verified status. You can view connected domains and their statuses in the control panel: in the top menu, click Products → Mail Service → Resource page → Information tab → Bound Domains block.

  2. Connect to the server in the Selectel infrastructure from which you plan to send mailings:

    Connect to the server via SSH or KVM console.

  3. Install sSMTP:

    sudo apt update
    sudo apt install ssmtp

  4. Install the mailx helper utility to send mail:

    sudo apt install mailutils

  5. Install nano:

    sudo apt install nano

  6. Open the ssmtp.conf configuration file:

    nano /etc/ssmtp/ssmtp.conf

  7. Change the contents of the file:

    mailhub=smtp.mail.selcloud.ru:<port>
    AuthUser=<login>
    AuthPass=<password>
    AuthMethod=LOGIN
    rewriteDomain=<example.com>
    hostname=smtp.mail.selcloud.ru
    FromLineOverride=No
    UseSTARTTLS=Yes
    UseTLS=Yes
    # Если <port>=1126, то UseTLS=No
    TLS_CA_File=/etc/ssl/certs/ca-certificates.crt

    Specify:

    • <port> — port:

      • 1126 — if you need to establish a no SSL / STARTTLS connection;
      • 1127 — if you want to establish a TLS (SSL) connection.

    • <login> — login, can be viewed in control panel: in the top menu click Products → Mail service → the page of the resource to which the domain has been added → tab Info;

    • <password> — password, can be viewed in control panel: in the top menu, click Products → Mail service → the page of the resource to which the domain has been added → tab Info;

    • <example.com> — domain from which to send mailings.

  8. Close the file **(Ctrl+X **) and save your changes ( **Y **).

  9. Open the revaliases configuration file:

    sudo nano /etc/ssmtp/revaliases

  10. Add a string with the address to be displayed as the sender's address in mailings through the mailing service:

    root:<sender_email>:smtp.mail.selcloud.ru:<port>

    Specify:

    • <sender_email> — sender address on the domain you have connected to your mail service, e.g. sender@example.com;
    • <port> — the port you specified in step 7.

  11. Close the file **(Ctrl+X **) and save your changes ( **Y **).

  12. Replace the default mail sender with the configured sSMTP:

    sudo mv /usr/sbin/sendmail /usr/sbin/sendmail.orig

  13. Create a symlink to ssmtp instead of sendmail:

    sudo ln -s /usr/sbin/ssmtp /usr/sbin/sendmail

  14. Send a test mailing:

    $ echo test | mail -s "testing ssmtp" <recipient_email>

    Specify <recipient_email> — the address to which you want to send the test mailing.