boulder/test/config/notify-mailer.json

{
  "notifyMailer": {
    "server": "localhost",
    "port": "9380",
    "username": "cert-master@example.com",
    "passwordFile": "test/secrets/smtp_password",
    "dbConnectFile": "test/secrets/mailer_dburl",
    "maxDBConns": 10
  }
}