code: func ClearEntriesForNAT(execer exec.Interface, origin, dest string, protocol v1.Protocol) error {
  	parameters := parametersWithFamily(utilnet.IsIPv6String(origin), "-D", "--orig-dst", origin, "--dst-nat", dest,
  		"-p", protoStr(protocol))
  	err := Exec(execer, parameters...)
  	if err != nil && !strings.Contains(err.Error(), NoConnectionToDelete) {
  		// TODO: Better handling for deletion failure. When failure occur, stale udp connection may not get flushed.
  		// These stale udp connection will keep black hole traffic. Making this a best effort operation for now, since it
  		// is expensive to baby sit all udp connections to kubernetes services.
  		return fmt.Errorf("error deleting conntrack entries for UDP peer {%s, %s}, error: %v", origin, dest, err)
  	}
  	return nil
  }
docs: // ClearEntriesForNAT uses the conntrack tool to delete the conntrack entries
  // for connections specified by the {origin, dest} IP pair.