Hi There are two processes about routing. (as deepak email said) Forwarding is a process of moving packets from input to output based on: - Forwarding Table - Information in the Packet. Routing: The Process by which the Forwarding table is built and maintianed. - One or more routing protocols - Procedures to converting routing information to forwarding table. Forwarding is handled by Forwarding Information Bases (FIB) or Forwarding Tables, which runs quite independent of the rouitng protocol''s Tables. The FIBs are derived from the routing tables ( on lesser systems, the routing table can be directly used for forwarding) I want to know under Linux how is FIB derived from routing table Can I control which routes are selected to be installed into Forwarding Tables --by varying the route preferences For example, I want put routing table into forwarding table by order of prefix /8.../10..../24.../30.. This order will make worse case lookup according to longest perfix match.. thanks yuxiao _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/