Assigning preferences in gated
A default preference is assigned to each source from which
gated receives routes. Preference values range from 0 to 255
with the lowest number indicating the most preferred route.
Table 5-2, ``Default preferences set by gated'', summarizes the default preference values for routes learned in various ways. The table lists the statements (some of these are clauses within statements) that set the preference and shows the types of routes to which each statement applies. The default preference for each type of route is listed. Comparison of default preferences in the table shows preference precedence between protocols. The narrower the scope of the statement, the higher precedence its preference value is given, but the smaller the set of routes it affects.
Table 5-2 Default preferences set by gated
------------------------------------------------------------------- Preference of Defined by statement Default ------------------------------------------------------------------- directly connected networks interface 0 OSPF routes ospf 10 internally generated default gendefault 20 redirects redirect 30 static routes from config static 60 RIP routes rip 100 point-to-point interface 110 routes to interfaces that are down interfaces 120 OSPF AS external routes ospf 150 BGP routes bgp 170 EGP egp 200Following are some sample preference specifications.
interfaces { interface 138.66.12.2 preference 10 ; } ; rip yes { preference 90 ; } ; import proto rip gateway 138.66.12.1 preference 75 ;In these statements, the preference applicable to routes learned via RIP from gateway 138.66.12.1 is 75. The last preference applicable to routes learned via RIP from gateway 138.66.12.1 is defined in the accept statement. The preference applicable to other RIP routes is found in the rip statement. The preference set on the interface statement applies only to the route to that interface.