Verified. Instead of using SMTPTLS in sendmail settings page, I just used “sendmail”. This now works exactly as expected, which is: 1. All outgoing emails are sent to mail relay via postfix 2. All outgoing emails are logged in /var/log/mail.log 3. If mail relay is inoperable, emails queue via postfix It is still a mystery to me how the mails are being sent when SMTPTLS is in use. Either way, just using the system’s configured MTA is preferable. Thanks anyone who read. -- John From: John Meyermailto:John.Meyer@secnap.com Sent: Friday, February 12, 2016 7:30 PM To: otrs@otrs.orgmailto:otrs@otrs.org Subject: Re: [otrs] Outbound email queue Postfix and I usually get along very well, I'd like to continue using it if at all possible. If I send an email from the command line, such as "echo test | mail email@address.commailto:%20email@address.com" that email is sent by postfix and is seen in /var/log/mail.log, however no emails from OTRS are logged here; but they do go through the mail relay. The question is, how is OTRS sending the mail? If I remove the sendmail settings from the OTRS web interface will it then simply send via the configured MTA, Postfix? Thanks, John Meyer ------ Original message------ From: David Boyes Date: Fri, Feb 12, 2016 7:14 PM To: User questions and discussions about OTRS.; Subject:Re: [otrs] Outbound email queue I am using OTRS with SMTPTLS to send all email to an outbound mail relay (postfix) and this is working perfectly. However, I am unable to locate where the logs are being stored. Normally, /var/log/mail, or wherever syslog puts the mail.* entries. See /etc/syslog.conf. Also, if by some chance my outbound relay isn’t operating as expected, OTRS does not appear to be queueing the emails the way I would expect (like postfix does). Working as designed. A MTA does queuing, not the application. What is OTRS using to send mail? Can I make it use postfix? OS is Debian. Consider using something a little less weird than postfix (exim comes to mind) but yes, that's the desired setup. See https://otrs.github.io/doc/manual/admin/3.2/en/html/email-settings.html for details for at least one version.