Mail Express Enterprise is a high-performance, stable, customizable, and secure SMTP server for your company or organization. It works as NT service with a advanced and high efficiency delivery engine. Users not only can use the DNS servers, delivery engines and rules in server, but also can customize their own DNS servers, delivery engines, rules, and their own IPs, all these management are in user's own computer by a Client Monitor. As a enterprise level SMTP server, there are complete secure safeguards in it, such as advanced IP filter, user authentication, etc. Client users can also add their own IP list into their own account to protect account against other users.