MailerQ!

Sendmail is a general purpose internetwork email routing facility that supports many kinds of transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet. A descendant of the delivermail program written by Eric Allman, Sendmail is a well-known project of the free and open source software and Unix communities, and has spread both as free software and proprietary software.

PowerMTA is an “enterprise” grade infrastructure application for email built to address the challenges of critical digital messaging environments and customer communications. PowerMTA™ is (advanced smtp software) providing unsurpassed reliability and delivery execution, with granular connection controls. Offering superior message throughput, simplified set up and configuration, and visibility through real-time reporting and tracking, PowerMTA™ pays dividends immediately. It is built on advanced multi-threaded persistent architecture—for messaging breakthrough that delivers unsurpassed resilience and performance. »

EmailSuccess is an advanced SMTP Server (MTA) derived from the technology and the expertise accumulated in years of exchanges with the ISP and ESP worlds, built from the ground up to handle the most critical reliability, performance, security, and deliverability requirements.