kumo.on('smtp_server_connection_accepted', function(conn_meta))

Since: Dev Builds Only

The functionality described in this section requires a dev build of KumoMTA. You can obtain a dev build by following the instructions in the Installation section.

Called by the ESMTP server when a new server session has accepted a connection from a client.

This event is triggered before sending the initial banner response, giving you the opportunity to decide whether to reject the connection, or continue.

If you do not reject the connection, then the server will continue with returning the banner to the client as normal.

The Connection Metadata object is passed as the only parameter, which can be used to determine information about the peer, and can be modified to track additional context throughout the lifetime of this particular connection.

kumo.on('smtp_server_connection_accepted', function(conn_meta)
  local peer = conn_meta:get_meta 'received_from'
  -- is_peer_deny_listed is some hypothetical function you
  -- define that will check to see if you want to allow this
  -- connection to continue
  if is_peer_deny_listed(peer) then
    kumo.reject(421, string.format('service not accepted from %s', peer))
  end
end)