The IPRIP_ROUTE_FILTER structure is used to specify a route filter for use in the IC_AcceptFilter and IC_AnnounceFilter fields of the IPRIP_IF_CONFIG (section 2.2.1.2.166) structure.  

 typedef struct _IPRIP_ROUTE_FILTER {
   DWORD RF_LoAddress;
   DWORD RF_HiAddress;
 } IPRIP_ROUTE_FILTER,
  *PIPRIP_ROUTE_FILTER;

RF_LoAddress: The starting IPv4 address of the route filter specified in network byte order.

RF_HiAddress: The ending IPv4 address of the route filter specified in network byte order.