Dynamic Routing Rule Objects - D-Link DFL-260E User Manual

4.5.4. Dynamic Routing Rules
• Allowing the export of routes from a local routing tables to the OSPF AS.
• Allowing the export of routes from one OSPF AS to another OSPF AS.
OSPF Requires at Least an Import Rule
By default, NetDefendOS will not import or export any routes. For OSPF to function, it is therefore
mandatory to define at least one dynamic routing rule which will be an Import rule.
This Import rule specifies the local OSPF Router Process object. This enables the external routes
made available in the OSPF AS to be imported into the local routing tables.
Specifying a Filter
Dynamic routing rules allow a filter to be specified which narrows the routes that are imported
based on the network reached. In most cases, the Or is within option should be specified as all-nets
so that no filter is applied.
When to Use Export Rules
Although an Import rule is needed to import routes from the OSPF AS, the opposite is not true. The
export of routes to networks that are part of OSPF Interface objects are automatic.
The one exception is for routes on interfaces that have a gateway defined for them. In other words,
where the destination is not directly connected to the physical interface and instead there is a hop to
another router on the way to the destination network. The all-nets route defined for Internet access
via an ISP is an example of such a route.
In this case, a dynamic routing export rule must be created to explicitly export the route to the OSPF
AS.

Dynamic Routing Rule Objects

The diagram below shows the relationship between the NetDefendOS dynamic routing rule objects.
Note
The last usage of joining asynchronous systems together is rarely encountered except
in very large networks.
Figure 4.13. Dynamic Routing Rule Objects
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Chapter 4. Routing