TekSMTP is a Windows-compatible SMTP/POP3 server, including a GUI (TekSMTP Manager) and a service application. It works with Vista, Windows 7/8/10, 2008-2019 Server.

One of the outstanding features of TekSMTP is its easy-to-use user interface and simple design that enables users to navigate the application with ease. The user interface for user definitions is also straightforward, which makes it easy to customize and define preferences for each user.
Another notable feature of TekSMTP is its multi-domain operation capability that enables it to serve multiple domains concurrently. The application's support for both POP3 and SMTP protocols have built-in TLS encryption, providing additional security for your email system.
TekSMTP also comes equipped with customizable SMTP ports, blacklisting, and RBL for anti-spam features that prevent unsolicited messages from flooding your inbox. The application has a POP3 password discovery feature that enables smooth migration, while its performance monitoring feature via Windows Performance Monitor ensures your email system's optimal performance.
TekSMTP has an RBL database that provides users with filtering options for SPAM messages. Users can also specify their DNS blacklists and connect systems directly. The software can check the validity of the sender's domain and supports SPF. E-mails can also be processed by defining and implementing user-specific rule sets.
Overall, TekSMTP is a reliable and easy-to-use email server application that offers a wide range of features essential for managing your email system effectively.
Version 1.5.4: Whitelisting (Version 1.5.4). DMARC policy check, DKIM signing and signature validation (Version 1.5.3).