dmth / flyingrat

A simple mail server for local development

Flying Rat

Flying Rat is a simple mail server for local development. It supports both SMTP to send messages and POP3 to fetch them.

All messages over SMTP are dropped into an .mbox-file named after the current date, which allows you to test your application with real email addresses without running the risk of actually sending messages to those recipients. Running a simple mail server also means it's a lot easier to configure your application to send those messages during local development. The SMTP server runs on localhost at port 5050 by default and that's all you need to configure.

When a message is received it's stored on disk, either to a temporary directory or a directory of your choosing:

flyingrat
Running from directory /tmp/tmpV1mYQY
SMTP on address localhost : 5050
POP3 on address localhost : 5051

This means you can examine the contents of the directory to view the actual message. But by default Flying Rat will also run a basic POP3 server on port 5051. It serves the file inbox.mbox by pop3.

Purpose

We at Intevation improved flyingrat to serve email to and from an offline ('airgapped') machine running Windows7 and Outlook 2010. Tested in this setting with Python2.7.

The emails can be saved to mbox format from an KDE Kontact (KMail) application running on Debian, put on a transport media (e.g. an USB-drive), uploaded to Outlook via flyingrat's POP3. Sending emails works via SMTPS to mbox and then transfered back.

Note that you must configure Outlook to delete emails when fetching them and using the right ports for POP3 and SMTP. Passwords must be configured, but flyingrat will accept them all. :)

Installing

You can install flyingrat using pip:

pip2 install .

You may also run the script directly, for instance:

python2 -m flyingrat.cli

Options

The most reliable source for possible options is the application itself. Just pass in the --help option:

flyingrat --help
usage: flyingrat [-h] [--version] [-m [{smtp,pop3,both}]] [-sa [SMTP_ADDRESS]]
                [-pa [POP3_ADDRESS]] [-pu [POP3_USER]] [-pp [POP3_PASSWORD]]
                [directory]

Create a POP3/SMTP server and serve contents of a local .mbox file

positional arguments:
directory             The directory where the .mbox files are

optional arguments:
-h, --help            show this help message and exit
--version             show program's version number and exit
-m [{smtp,pop3,both}], --mode [{smtp,pop3,both}]
                        Run smtp, pop3 or both (default)
-sa [SMTP_ADDRESS], --smtp-address [SMTP_ADDRESS]
                        Address to run the SMTP server on. Defaults to
                        localhost:5050
-pa [POP3_ADDRESS], --pop3-address [POP3_ADDRESS]
                        Address to run the POP3 server on. Defaults to
                        localhost:5051
-pu [POP3_USER], --pop3-user [POP3_USER]
                        Username for the POP3 server (default: <any>)
-pp [POP3_PASSWORD], --pop3-password [POP3_PASSWORD]
                        Password for the POP3 server (default: <any>)

Windows

The Mailserver is also running on Windows (tested with Windows 7). You require an installed Python2.7

To install flyingrat for your user, just run the file bin\install.cmd. Please make sure that the PythonPath was set correctly in bin\environment.cmd

To start the server, doubleclick bin\run.cmd, If you run bin\help.cmd you can get more information how the Server can be started on Windows.