SMTP Archives - Sysadmins of the North

Release hold queue email in Postfix – postsuper

6 August 2017
/ GNU Linux
/ By Jan Reilink
/

How to flush Postfix’ mail queue from the command line and delete all mail from the queue? Easy, use the Postfix postsuper command as explained in this post. The postsuper command controls different types of queues in the Postfix mail system, like the deferred or hold queue. This post shows you some Postfix queue operations to maintain your mail servers.

Send authenticated email over TLS from Zen Cart

24 April 2015
/ Code base
/ By Jan Reilink
/

Zen Cart is an open source shopping cart software. Unfortunately, Zen Cart has had some difficulties in the past sending authenticated SMTP email from a website. Here is how to let Zen Cart send email over an encrypted TLS connection, when the following condition is met: StartTLS is required. Since Zen Cart v1.5.2 StartTLS support is available.

Monit monitoring on Ubuntu 14.04 VM on Hyper-V

15 February 2015
/ GNU Linux
/ By Jan Reilink
/ 1 COMMENT
/

In this post you’ll learn about setting up a Monit monitoring service for your websites and services. Monit is a free and open source service monitoring application which can perform various event-based actions. Monit can send email notifications, restart a service or application, or take other responsive actions. We set Monit up on a Ubuntu 14.04 VM, built on Hyper-V. And we use Monit to monitor several websites, and send out notifications on downtime.

Send authenticated SMTP email over TLS from WordPress

29 July 2014
/ WordPress
/ By Jan Reilink
/ 1 COMMENT
/

How to configure TLS for SMTP email in WordPress. I was suprised WordPress is not able to send email using an SMTP server out-of-the-box. Not to mention using authenticated SMTP or TLS transport for security. A quick Google search showed me multiple plugins to handle this, but I wanted to create something myself. Here is how to override the wp-mail() function and send email using authenticated SMTP and StartTLS from WordPress.

Send email with Ghost using SMTP authentication and TLS encryption

19 June 2014
/ Windows Server
/ By Jan Reilink
/ 2 COMMENTS
/

Ghost Publishing platform uses Nodemailer to send e-mails with Node.js. It can send e-mail using SMTP, sendmail or Amazon SES and is unicode friendly.

SMTP over Hidden Services with postfix

17 June 2014
/ Security
/ By Jan Reilink
/

Into.the.Void. writes:
“This post is about sending SMTP traffic between two servers on the Internet over Tor, that is without someone being able to easily see who is sending what to whom. IMHO, it can be helpful in some situations to certain groups of people.”

How to delete all MAILER-DAEMON emails in Postfix queue

4 June 2014
/ GNU Linux
/ By Jan Reilink
/ 2 COMMENTS
/

How to delete all MAILER-DAEMON emails from your Postfix queue, when it matches a sender or recipient email address condition. When a large scale spam run was sent through your mail servers, you need to clean up and remove those spam messages. Doing so guarantees normal, valid email messages being sent quickly, and the spam messages never leave your queue. In Postfix, there are various similar commands to delete messages from the Postfix mail queue. Based on the Message-ID and/or email address…

How to test SMTP Authentication and StartTLS

17 May 2014
/ Security
/ By Jan Reilink
/ 9 COMMENTS
/

How to test SMTP authentication and StartTLS using the command line?

When investigating SMTP authentication issues, particular over TLS encrypted SMTP connections, it’s always handy if you are able to test the SMTP authentication and StartTLS connection. Preferably from your command line. This post shows you how to test SMTP servers, verify SMTP authentication and StartTLS encrypted connections from the Linux and Windows command line.

Add (custom) headers to MailMessage class

23 April 2014
/ Code base
/ By Jan Reilink
/

How to add custom headers to System.Net.Mail? When sending an email using the MailMessage class (System.Net.Mail namespace) in an ASP.NET website, certain email headers like Message-ID are not always set. When a Message-ID header is missing, email might be blocked by the recipients SMTP server. Therefore it is necessary to set such headers…

How to send authenticated SMTP over a TLS encrypted connection, in PHP, ASP and ASP.NET?

15 May 2013
/ Code base
/ By Jan Reilink
/ 6 COMMENTS
/

Send authenticated SMTP (auth-SMTP) over a TLS encrypted connection. If you want to send email securely from your website, this post is for you! In this post I’ll provide some script examples for ASP, PHP, and ASP.NET (C# / VB.Net) that you can easily integrate in your website.