code: func ClearEntriesForPortNAT(execer exec.Interface, dest string, port int, protocol v1.Protocol) error {
  	if port <= 0 {
  		return fmt.Errorf("Wrong port number. The port number must be greater then zero")
  	}
  	parameters := parametersWithFamily(utilnet.IsIPv6String(dest), "-D", "-p", protoStr(protocol), "--dport", strconv.Itoa(port), "--dst-nat", dest)
  	err := Exec(execer, parameters...)
  	if err != nil && !strings.Contains(err.Error(), NoConnectionToDelete) {
  		return fmt.Errorf("error deleting conntrack entries for UDP port: %d, error: %v", port, err)
  	}
  	return nil
  }
docs: // ClearEntriesForPortNAT uses the conntrack tool to delete the contrack entries
  // for connections specified by the {dest IP, port} pair.
  // Known issue:
  // https://github.com/kubernetes/kubernetes/issues/59368