fix bug caused by Google's attack on DNS infrastructure.

pkg/meshname/server.go

@@ -145,6 +145,9 @@ func (s *MeshnameServer) handleMeshnameRequest(w dns.ResponseWriter, r *dns.Msg)
 		rm := new(dns.Msg)
 		rm.RecursionDesired = true
 		rm.Question = questions
+		// always use lowercase internally among meshname instances
+		rm.Question[0].Name = strings.ToLower(rm.Question[0].Name)
+		s.log.Debugln(rm.Question[0].Name) // DEBUG
 		// add alternative port number
 		portNumbers := []string{"53"}
 		portNumbers = append([]string{s.acmePort}, portNumbers...)  // TODO: rename acmePort to alternativePort