Mailrelay

Mailrelay is a single container email relay server intended for forwarding email to a personal email account like Gmail or Outlook. For those who don’t like to forward their email to a service like Gmail, it also has POP3 support.

Quick start

If you have Docker and Docker Compose installed, you can just run the quick start script to spin up a demo service:

$ ./quick-start.sh

Don't use this in production!

Installation instructions

Prerequisites

You need a valid TLS certificate for your hostname in order to use Mailrelay, you can get one for free from Let's Encrypt. You also need a PostgreSQL server to host the Mailrelay database.

Step 1: Setup the database

Let's create the database first, assuming you already have a working PostgreSQL server. One way is to execute these simple commands:

$ psql -c "CREATE DATABASE mailrelay;"
$ cat schema.sql | psql mailrelay

The database should now be created.

Step 2: Create your configuration directory

It's recommended to store Mailrelay's configuration at one place such as /opt/mailrelay. Create this directory and copy your TLS certificate along with its private key to a subdirectory /opt/mailrelay/tls, make sure the PEM files are named cert.pem and privkey.pem.

Step 3: Create the container

Run the following command, after filling out the variable <<VAR>> parts, to create and run the container:

docker run -d --name mailrelay \
    --hostname "<<YOUR HOSTNAME>>" \
    -e MAILRELAY_PSQL_HOST="<<YOUR POSTGRES HOSTNAME>>" \
    -e MAILRELAY_PSQL_DB="<<YOUR POSTGRES DATABASE NAME>>" \
    -e MAILRELAY_PSQL_USER="<<YOUR POSTGRES USER NAME>>" \
    -e MAILRELAY_PSQL_PASSWORD="<<YOUR POSTGRES USER PASSWORD>>" \
    -v /opt/mailrelay:/opt/mailrelay \
    -e MAILRELAY_DKIM_GENERATE="true" \
    -e MAILRELAY_CREATE_STUB="true" \
    docker.pkg.github.com/semrekkers/mailrelay/mailrelay

Step 4: Add your DKIM public key record to your hostname's DNS

If you enabled the MAILRELAY_DKIM_GENERATE option then you can find your DKIM public key record at /opt/mailrelay/dkim/record.txt. Create a new DNS TXT record named default._domainkey with the contents of the record.txt starting with v=DKIM1; k=rsa; p=....

Environment variables

Name	Description	Default value
TZ	Timezone name	`Etc/UTC`
HOSTNAME	Hostname
MAILRELAY_ROOT	Root directory for static configuration	`/opt/mailrelay`
MAILRELAY_VMAIL	Virtual mail directory	`/opt/mailrelay/vmail`
MAILRELAY_TLS_CERT	TLS certificate file	`/opt/mailrelay/tls/cert.pem`
MAILRELAY_TLS_KEY	TLS private key file	`/opt/mailrelay/tls/privkey.pem`
MAILRELAY_PSQL_HOST	PostgreSQL hostname	`postgres`
MAILRELAY_PSQL_DB	PostgreSQL database name	`postgres`
MAILRELAY_PSQL_USER	PostgreSQL username	`postgres`
MAILRELAY_PSQL_PASSWORD	PostgreSQL user password
MAILRELAY_DKIM_SELECTOR	DKIM selector	`default`
MAILRELAY_DKIM_KEY	DKIM private key file	`/opt/mailrelay/dkim/privkey.pem`
MAILRELAY_DKIM_RECORD	DKIM public key record file	`/opt/mailrelay/dkim/record.txt`
MAILRELAY_DKIM_GENERATE	Generate DKIM key pair when `true`
MAILRELAY_CREATE_STUB	Create stub directories (vmail, tls and dkim) when `true`

Contributions and issues

Found an issue or have a question? Please open up an issue!