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kumo.on('smtp_server_mail_from', function(sender, conn_meta))

Called by the ESMTP server in response to the client issuing a "MAIL FROM" command. The event handler is passed the sender address parameter from the MAIL FROM command.

The sender address is an EnvelopeAddress object.

Since: Version 2023.08.22-4d895015

The functionality described in this outlined box requires version 2023.08.22-4d895015 of KumoMTA, or a more recent version.


The conn_meta parameter represents the connection metadata and can be used to share state between the various SMTP listener event handlers. See Connection Metadata for more information.

You may choose to reject the connection via kumo.reject.

kumo.on('smtp_server_mail_from', function(sender)
  if sender.domain == 'bad.domain' then
    kumo.reject(420, 'not thanks')
  end
end)