nixpkgs/nixos/modules/services/mail/mailman.md

Mailman

Mailman is free software for managing electronic mail discussion and e-newsletter lists. Mailman and its web interface can be configured using the corresponding NixOS module. Note that this service is best used with an existing, securely configured Postfix setup, as it does not automatically configure this.

Basic usage with Postfix

For a basic configuration with Postfix as the MTA, the following settings are suggested:

{ config, ... }: {
  services.postfix = {
    enable = true;
    relayDomains = ["hash:/var/lib/mailman/data/postfix_domains"];
    sslCert = config.security.acme.certs."lists.example.org".directory + "/full.pem";
    sslKey = config.security.acme.certs."lists.example.org".directory + "/key.pem";
    config = {
      transport_maps = ["hash:/var/lib/mailman/data/postfix_lmtp"];
      local_recipient_maps = ["hash:/var/lib/mailman/data/postfix_lmtp"];
    };
  };
  services.mailman = {
    enable = true;
    serve.enable = true;
    hyperkitty.enable = true;
    webHosts = ["lists.example.org"];
    siteOwner = "mailman@example.org";
  };
  services.nginx.virtualHosts."lists.example.org".enableACME = true;
  networking.firewall.allowedTCPPorts = [ 25 80 443 ];
}

DNS records will also be required:

• AAAA and A records pointing to the host in question, in order for browsers to be able to discover the address of the web server;
• An MX record pointing to a domain name at which the host is reachable, in order for other mail servers to be able to deliver emails to the mailing lists it hosts.

After this has been done and appropriate DNS records have been set up, the Postorius mailing list manager and the Hyperkitty archive browser will be available at https://lists.example.org/. Note that this setup is not sufficient to deliver emails to most email providers nor to avoid spam -- a number of additional measures for authenticating incoming and outgoing mails, such as SPF, DMARC and DKIM are necessary, but outside the scope of the Mailman module.

Using with other MTAs

Mailman also supports other MTA, though with a little bit more configuration. For example, to use Mailman with Exim, you can use the following settings:

{ config, ... }: {
  services = {
    mailman = {
      enable = true;
      siteOwner = "mailman@example.org";
      enablePostfix = false;
      settings.mta = {
        incoming = "mailman.mta.exim4.LMTP";
        outgoing = "mailman.mta.deliver.deliver";
        lmtp_host = "localhost";
        lmtp_port = "8024";
        smtp_host = "localhost";
        smtp_port = "25";
        configuration = "python:mailman.config.exim4";
      };
    };
    exim = {
      enable = true;
      # You can configure Exim in a separate file to reduce configuration.nix clutter
      config = builtins.readFile ./exim.conf;
    };
  };
}

The exim config needs some special additions to work with Mailman. Currently NixOS can't manage Exim config with such granularity. Please refer to Mailman documentation for more info on configuring Mailman for working with Exim.