MAC_PLUGIN_IDENT_6TO4
{ IPTUN_TYPE_6TO4, MAC_PLUGIN_IDENT_6TO4, IPV4_VERSION,
mtrp->mtr_ident = MAC_PLUGIN_IDENT_6TO4;
(void) mactype_unregister(MAC_PLUGIN_IDENT_6TO4);
if ((err = mactype_unregister(MAC_PLUGIN_IDENT_6TO4)) != 0)