This article is about the electronic mail transfer agent. In March 2017 the exim smtp mail server pdf a study performed by E-Soft, Inc. 3, but it has since diverged from Smail-3 in its design and philosophy.
Exim is highly configurable, and therefore has features that are lacking in other MTAs. It has always had substantial facilities for mail policy controls, providing facilities for the administrator to control who may send or relay mail through the system. This made Exim very suitable for enforcing diverse mail policies. The configuration file permits inclusion of other files, which leads to two different configuration styles. There are two main schools of configuration style for Exim. In these approaches, a debconf configuration file is used to build the Exim configuration file, together with templates and directories with configuration fragments.
Debian questions on the Debian-managed mailing-list. The Exim Specification is available in multiple formats, including online in HTML and in plain-text for fast searching. The document preparation system ensures that the plain-text format is highly usable. Exim has been deployed in busy environments, often handling thousands of emails per hour efficiently. Exim is designed to deliver email immediately, without queueing. The bottom line is that Exim does not perform particularly well in environments where the queue regularly gets very large.