Linux / MacOS


Install Stalwart SMTP server by running the following command in your terminal:

curl --proto '=https' --tlsv1.2 -sSf | sudo sh

Once the installation is completed, Stalwart SMTP will be available under the /usr/local/stalwart-smtp directory. The installation script will also create the stalwart-smtp account and start the stalwart-smtp systemd/launchd service.

Please note that root access is required to perform the installation, if you don’t feel comfortable running the install script as root you may also download the latest release and perform a manual installation.

Set up

The installation script will ask you to enter your server’s fully-qualified domain-name (FQDN), your domain name (you can add more domains later) and the administrator’s password (used by the management REST API). Additionally you’ll have to provide the address and port to use to deliver messages to your message store (e.g.: Stalwart JMAP, Dovecot, Courier-IMAP, etc.) over the LMTP protocol:

Enter the SMTP server's hostname []:
Enter your domain name []:
Enter the SMTP server's administrator password [changeme]: my_secret_pass
Enter your LMTP server's hostname [localhost]: localhost
Enter your LMTP server's port [24]: 24

If everything is correct, you should now be able to connect to Stalwart SMTP on ports 25, 587 and 465 (using a self-signed certificate), but before it can start accepting connections from SMTP clients, you’ll have to install valid a TLS certificate.


Stalwart SMTP requires a valid TLS certificate in order to operate. If you currently don’t have a TLS certificate, you can obtain one for free from Let’s Encrypt. Once you have your certificate ready, copy your certificate and private key to their default locations as follows:

sudo cp mycert.crt /usr/local/stalwart-smtp/etc/certs/tls.crt
sudo cp mykey.key /usr/local/stalwart-smtp/etc/private/tls.key


DomainKeys Identified Mail (DKIM) is a method of email authentication that allows a receiving email server to verify that an email message was actually sent by the owner of the domain from which it appears to have been sent. It is highly recommended that you enable DKIM (as well as SPF and DMARC) for your domain. The installation script will automatically generate a 2048 bits RSA certificate for your domain and print out the instructions to enable DKIM in your DNS server:

To enable DKIM please add the following record to your DNS server:

Value: v=DKIM1; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAux8eFQWzgUCHZ105H+D+oDI/tzovKRYInWIAq2pH1H1Osr5jKMhbN2fKW3f9gk810cC50aR4oo2DRKfwUqDlLJmum6UWfcliSwTwIDloGnUTWNeSw3U/ZvsmMAg00rwWA2OxPj59se7ElwfDICEPlxuePxI8l+TaAbq1fN4OJPJOC9ERn11JslR5D/wLIzKX5e6mM4MnNfo2dC0y7JKtn6w0gnNegERN3gmdPLnxccMhVBHYkQz2rPYOki5jnGkRuhcY0F1X+wVgRbiuaBv4X5VbebheyOjsv/bxRwAWVYFwCQJP1FoG7lQbr3YtCQihR8RzVclvSL8Y68uxL+qHwQIDAQAB
Type: TXT
TTL: 86400

If you already have a DKIM certificate simply ignore these instructions and refer to the DKIM section for instructions on how to add a new DKIM signature.

Restart service

Once you have completed the setup instructions, restart your Stalwart SMTP server:

sudo systemctl restart stalwart-smtp

Or, if you are using MacOS:

sudo launchctl kickstart -k stalwart.smtp

Next steps

Now that you have Stalwart SMTP up and running, you may want to enable SASL authentication using your IMAP4 server or SQL database.