Outgoing messages

doe-family.com/outgoing.vsl is run when the sender of the domain is doe-family.com and that recipients domains are not doe-family.com.

Here, a member of Doe’s family is sending an email to someone else. We just have to verify that the sender is legitimate by asking the client to authenticate itself to vSMTP. If the authentication fails, this probably means that a spammer tried to use our server as a relay. The auth::unix_user() function automatically denies the transaction if the authentication failed.

  authenticate: [
    rule "sasl authentication" || auth::unix_user(),

  mail: [
    rule "deny unauthenticated" || {
      if auth::is_authenticated() {
      } else {
        state::deny(code(530, "5.7.0", "Authentication required\r\n"))


⚠️ The auth::unix_user function uses the testsaslauthd program under the hood, itself calling the saslauthd daemon. Make sure to install the Cyrus sasl binary package for the targeted distribution and configure the saslauthd daemon with MECHANISM="shadow" in /etc/default/saslauthd.

See the auth::is_authenticated and auth::unix_user reference for more details.