docker-protonmail-personal-gateway

The goal of this docker image is to create a simple gateway that will intercept email notifications from appliances and devices that can send alerts over email, encrypt the content of the email and send it to my protonmail account, using the free gmail SMTP service. It should be fairly simple for you to clone this repo and replace the google SMTP with another provider.

Changes compared to tianon/exim4 and metabrainz/docker-exim:

it only forwards email addressed to my protonmail account
encrypts the body of the email with my protonmail public gpg key

Parameters

DOMAIN: optional, use it if you have a custom domain.
GMAIL_USER: your google id
GMAIL_PASSWORD: the google application password for your account.
PROTONMAIL_USER: your protonmail address
PROTONMAIL_USER_PUBLIC_KEY: path to your protonmail GPG public key
MYNETWORKS: Add additional networks to authorize relaying mails

You can mount the public gpg key with the -v/--volume command when you run docker. Set the mount location to the variable PROTONMAIL_USER_PUBLIC_KEY, it will get imported on start.

After getting a google application password, you may use something like:

docker run --detach --volume ~/Desktop/publickey.youruser@protonmail.com.asc:/tmp/gpgkey.pub --publish 12025:25 --env GMAIL_USER=youruser@yourdomain.com --env GMAIL_PASSWORD=yourapppasswordhere --env PROTONMAIL_USER=youruser@protonmail.com --env PROTONMAIL_USER_PUBLIC_KEY=/tmp/gpgkey.pub --env MYNETWORKS='192.168.5.0/24;192.168.5.0/24' --name pmgate blacs30/docker-protonmail-personal-gateway

Images are available at https://hub.docker.com/r/blacs30/docker-protonmail-personal-gateway

How to get my protonmail public key?

See https://protonmail.com/support/knowledge-base/download-public-key/

Credits

Exim docker image based on https://github.com/tianon/dockerfiles/tree/master/exim4, plus some improvements added by https://github.com/metabrainz/docker-exim Exim GPG plugin based on https://github.com/Interoberlin/exim-gpg-filter