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To force the autonomous system boundary router to generate a default route, perform the following task in router
configuration mode.
Command Purpose
redistribute {kernel | connected |
static | rip | bgp} [metric
metric-value
]
[metric-type {1|2}][route-map
map-tag
]
Redistribute routes into OSPF routing domain.
5.7.16 Change the OSPF Administrative Distances
An administrative distance is a value that rates the trustworthiness of a routing information source, such as an
individual router or a group of routers. Numerically, an administrative distance is an integer between 0 and 255. The
higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source
cannot be trusted at all and should be ignored.
OSPF uses three different administrative distances: intra-area, inter-area, and external. Routes learned through other
domains are external, routes to another area in OSPF domain are inter-area, and routes inside an area are intra-
area. The default distance for each type of route is 110.
To change any of the OSPF distance values, use the following command in router configuration mode.
Command Purpose
distance ospf {external
distance1
|
inter-area
distance2
|
intra-area
distance2
}
Change the OSPF administrative distance values.
5.7.17 Suppress Routes on an Interface
The interface specified as passive appears as a stub network in the OSPF domain. OSPF routing information is
neither sent nor received through that specified router interface.
To suppress routes on a specified interface, use the following command in router configuration mode.
Command Purpose
passive-interface
interface-name
Suppress the sending of routes through the specified
interface.
5.7.18 Prevent Routes from being Advertised in Routing Updates
To prevent other routers from learning one or more routes, you can suppress routes from being advertised in routing
updates. Note that this feature applies only to external routes.
To suppress routes from being advertised in routing updates, perform the following task in router configuration mode.
Command Purpose
distribute-list
list-name
out {bgp |
connected | kernel | rip | static}
Permit or deny routes from being advertised in routing
updates, depending upon the action listed in the access list.
