gpg-mailgate is a gateway for Postfix

that uses the GNU Privacy Guard application to encrypt e-mails before being sent to the next hop.

INSTALLATION:

Ensure that GPG is installed and configured.

Make sure public keys for all of your potential recipients are available in the GPG home directory you use in step 2

Configure /etc/gpg-mailgate.conf based on the provided sample config

Place gpg-mailgate.py in /usr/local/bin/

Place the GnuPG directory in /usr/local/lib/python2.5/site-packages

Add the following to the end of /etc/postfix/master.cf

    # gpg-mailgate    unix    -       n       n       -       -       pipe flags= user=nobody argv=/usr/local/bin/gpg-mailgate.py
    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

Add the following to /etc/postfix/main.cf: content_filter = gpg-mailgate

Restart postfix.