Can't Send Emails Using Both Postfix & Sendmail On Debian-9-64bit Fresh Droplet

April 8, 2018 518 views
Email Applications Conceptual DigitalOcean Cloud Firewalls Firewall Messaging Debian

There's a problem with either the DigitalOcean firewalls or something similar. Can't send emails using both Postfix and Sendmail. I've put no firewalls in place. All ports open, but still can't send. Please fix ASAP.

Steps to reproduce the case:

  1. Create a Debian-9-64bit 1GB droplet.
  2. Update system using apt-get update && apt-get dist-upgrade
  3. Now install Postfix using apt-get install postfix postfix-mysql postfix-doc openssl getmail4 rkhunter binutils dovecot-imapd dovecot-pop3d dovecot-mysql dovecot-sieve dovecot-lmtpd mailutils
  4. Send a test mail, echo "This is the body of the email" | mail -s "This is the subject line" youremailaddress Now, the mail never gets sent. Please look into this issue.
1 Answer

When you attempt to send an email by following these steps, what if anything is recorded in your postfix log files?

  • The issue has been fixed. It's due to DigitalOcean blocking outgoing IPv6-SMTP traffic. It's working fine on an IPv4-only droplet. On an IPv6 droplet, you can prioritize outgoing mail traffic through IPv4 address.

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