9.1 KiB

Installation instructions


  • General information
  • Install GPG-Mailgate
  • Install GPG-Mailgate-Web
  • Install Register-handler

General information

GPG-Mailgate is divided in 3 main parts: GPG-Mailgate itself, GPG-Mailgate-Web and Register-handler. Some parts of the GPG-Mailgate project depend on other parts of the project. You will find information about these dependencies at the beginning of every installation part.

These instructions show you how to set up GPG-Mailgate in an easy way. If you are a more advanced user, feel free to experiment with the settings. For these instructions a home directory for the user nobody is set. Sadly this is an odd workaround but no better solution was found.

These instructions are based on an installation on an Ubuntu 14.04 LTS virtual machine. For other Linux distributions and other versions these instructions might need to be adapted to your distribution (e.g. installation of packages and used directories).

Install GPG-Mailgate


  • Python 3.9.
  • Dependencies listed in requirements file, requirements.txt.
  • Postfix: installed, configured and tested.
  • GnuPG: installed, configured and tested (e.g. via command-line).


  1. Install the dependencies:
python -m pip install -r requirements.txt
  1. Set the home directory for the user nobody (sadly this workaround is needed as there is no better solution at this point). If you get an error that the user is currently used by a process, you might need to kill the process manually.
usermod -d /var/gpgmailgate nobody
  1. Create dedicated directories for storing PGP keys and S/MIME certificates and make the user nobody owner of these:
mkdir -p /var/gpgmailgate/.gnupg
mkdir -p /var/gpgmailgate/smime
chown -R nobody:nogroup /var/gpgmailgate/
  1. Place the in /usr/local/bin/, make the user nobody owner of the file and make it executable:
chown nobody:nogroup /usr/local/bin/
chmod u+x /usr/local/bin/
  1. Place the GnuPG directory in /usr/local/lib/python3.x/dist-packages (replace 3.x with your Python version)

  2. Configure /etc/gpg-mailgate.conf based on the provided gpg-mailgate.conf.sample. Change the settings according to your configuration. If you follow this guide and have a standard configuration for postfix, you don't need to change much.

  3. Configure logging by copying gpg-lacre-logging.conf.sample to /etc/gpg-lacre-logging.conf and editing it according to your needs. The path to this file is included in [logging] section of gpg-mailgate.conf file, so if you place it somewhere else, make sure to update the path too. See also: Configuration file format.

  4. Add the following to the end of /etc/postfix/

gpg-mailgate    unix    -   n   n   -   -   pipe
    flags= user=nobody argv=/usr/local/bin/ ${recipient}

127. 0. 0. 1:10028 inet    n   -   n   -   10  smtpd
    -o content_filter=
    -o receive_override_options=no_unknown_recipient_checks,no_header_body_checks
    -o smtpd_helo_restrictions=
    -o smtpd_client_restrictions=
    -o smtpd_sender_restrictions=
    -o smtpd_recipient_restrictions=permit_mynetworks,reject
    -o mynetworks=127. 0. 0. 0/8
    -o smtpd_authorized_xforward_hosts=127. 0. 0. 0/8

If you use Postfix versions from 2.5 onwards, it is recommended to change ${recipient} to ${original_recipient} in line two of the lines above.

  1. Add the following line to /etc/postfix/
content_filter = gpg-mailgate
  1. Optional: GPG can automatically download new public keys for automatic signature verification. To enable automatic create the file /var/gpgmailgate/.gnupg/gpg.conf. Add the following line to the file:
keyserver-options auto-key-retrieve
  1. Restart Postfix

You are now ready to go. To add a public key for encryption just use the following command:

sudo -u nobody /usr/bin/gpg --homedir=/var/gpgmailgate/.gnupg --import /some/public.key
  • Replace /some/public.key with the location of a public key
  • /some/public.key can be deleted after importation
  • Confirm that it's working: sudo -u nobody /usr/bin/gpg --list-keys --homedir=/var/gpgmailgate/.gnupg

Please also test your installation before using it.

GPG-Mailgate is also able to handle S/MIME certificates for encrypting mails. However, it is best to use it in combination with Register-Handler described later to add new certificates. If you try to add them manually it might fail. The certificates are stored in /var/gpgmailgate/smime in PKCS7 format and are named like (the user part is case sensitive, the domain part should be in lower case).

Additional settings

Most mail servers do not handle mail addresses case sensitive. If you know that all your recipient mail servers do not care about case sensitivity then you can set mail_case_insensitive in the settings to yes so looking up PGP keys or S/MIME certificates does also happen case insensitive. If your recipients have problems to decrypt mails encrypted by GPG-Mailgate they might use a piece of software that does not support PGP/MIME encrypted mails. You can tell GPG-Mailgate to use the legacy PGP/INLINE format by adding the recipient to the pgp_style map in the following format:

Install GPG-Mailgate-Web


  • A webserver is installed and reachable
  • The webserver is able to handle PHP scripts
  • MySQL is installed
  • Python 3.x is already installed


All files you need can be found in the Lacre / lacre-webgate repository.

  1. Install the Python-mysqldb and Python-markdown modules:
apt-get install python-mysqldb python-markdown
  1. Create a new database for GPG-Mailgate-Web.

  2. Import the schema file schema.sql into the newly created database.

  3. Edit the config file located at /etc/gpg-mailgate.conf. Set enabled = yes in [database] and fill in the necessary settings for the database connection.

  4. Copy the files located in the public_html directory onto your webserver. They can also be placed in a subdirectory on your webserver.

  5. On your webserver move the config.sample.php file to config.php and edit the configuration file.

  6. Create directories for storing email templates:

mkdir -p /var/gpgmailgate/cron_templates
  1. Copy the templates found in the cron_templates directory into the newly created directory and transfer ownership:
chown -R nobody:nogroup /var/gpgmailgate/cron_templates
  1. Copy to /usr/local/bin/ Make it executable and and transfer ownership to nobody:
chown nobody:nogroup /usr/local/bin/
chmod u+x /usr/local/bin/
  1. Create /etc/cron.d/gpgmw with contents: */3 * * * * nobody /usr/bin/python /usr/local/bin/ > /dev/null for executing the cron job automatically.

  2. Test your installation.

GPG-Mailgate-Web as keyserver

GPG-Mailgate-Web can also be used as a keyserver. For more information have a look at GPG-Mailgate-Web's readme.

Install Register-handler


  • Already set up and working GPG-Mailgate-Web. It should be reachable from the machine that will run register-handler
  • Postfix is already installed and configured. It is recommended that you have already tested your configuration so we can exclude this as a main cause of problems. Your Postfix configuration should also support aliases


  1. Install the Python-requests module:
apt-get install python-requests
  1. Create directories for storing email templates:
mkdir -p /var/gpgmailgate/register_templates
  1. Copy the templates found in the register_templates directory into the newly created directory and transfer ownership:
chown -R nobody:nogroup /var/gpgmailgate/register_templates
  1. Copy to /usr/local/bin/ Make it executable and own it to nobody:
chown nobody:nogroup /usr/local/bin/
chmod a+x /usr/local/bin/
  1. Edit the config file located at /etc/gpg-mailgate.conf. Set the parameter webpanel_url in [mailregister] to the url of your GPG-Mailgate-Web panel (the URL should be the same as the one you use to access the panel with your web browser). Also set the parameter register_email to the email address you want the user to see when receiving mails from the register-handler (it does not have to be an existing address but it is recommended). Register-handler will send users mails when they are registering S/MIME certificates or when neither a S/MIME certificate nor a PGP key was found in a mail sent to the register-handler.

  2. Add register: |/usr/local/bin/ to /etc/aliases

  3. Update postfix's alias database with postalias /etc/aliases

  4. Restart postfix.

  5. Test your installation.