Technical data

Gateway Routing Daemon (GATED) Configuration Reference
A.18 Control Statements
A.18.3.5 Importing Routes from OSPF
Use the following syntax to define importing routes from OSPF:
import proto ospfase [ tag ospf_tag ] restrict ;
import proto ospfase [ tag ospf_tag ]
[ preference preference ]{
route_filter [ restrict | ( preference preference )];
};
Due to the nature of OSPF, only the importation of ASE routes may be controlled.
OSPF intra- and inter-area routes are always imported into the GATED routing
table with a preference of 10. If a tag is specified, the import clause will only
apply to routes with the specified tag.
It is only possible to restrict the importation of OSPF ASE routes when
functioning as an AS border router. This is accomplished by specifying an export
ospfase clause. Specification of an empty export clause may be used to restrict
importation of ASEs when no ASEs are being exported.
Like the other interior protocols, preference can not be used to choose between
OSPF ASE routes, that is done by the OSPF costs. Routes that are rejected by
policy are stored in the table with a negative preference.
A.18.4 The Export Statement
The import statement controls which routes received from other systems are used
by GATED; the export statement controls which routes are advertised by GATED
to other systems. Like the import statement, the syntax of the export statement
varies slightly per protocol. The syntax of the export statement is similar to the
syntax of the import statement, and the meanings of many of the parameters are
identical. The main difference between the two is that while route importation
is just controlled by source information, route exportation is controlled by both
destination and source.
The outer portion of a given export statement specifies the destination of the
routing information you are controlling. The middle portion restricts the sources
of importation that you wish to consider. And the innermost portion is a route
filter used to select individual routes.
A.18.4.1 Specifying Metrics
The most specific specification of a metric is the one applied to the route being
exported. The values that may be specified for a metric depend on the destination
protocol that is referenced by this export statement.
restrict
metric metric
In this syntax:
•
restrict specifies that nothing should be exported. If specified on the
destination portion of the export statement it specifies that nothing at all
should be exported to this destination. If specified on the source portion it
specifies that nothing from this source should be exported to this destination.
If specified as part of a route filter it specifies that the routes matching that
filter should not be exported.
• metric metric specifies the metric to be used when exporting to the specified
destination.
Gateway Routing Daemon (GATED) Configuration Reference A–37