[Postfix](http://www.postfix.org/) is a popular open-source [Mail Transfer Agent](https://en.wikipedia.org/wiki/Message_transfer_agent) (MTA) that can be used to route and deliver email on a Linux system. It is estimated that around 25% of public mail servers on the internet run Postfix. In this guide, you’ll install, configure and test Postfix on your server. Choose your operating system below to get started.