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Beginner

How can i distribute a default route in a specific area in OSPF?

INGLES:

Well my problem is the next one i want to distribute a default route in a specific area but only on this area in OSPF ipv4 and ipv6,

IF a have areas 0, 1 and 2 and the router ABR between area 0 and area 1 have a default route pointing to 192.168.0.1/24 how can i distribute this route only in the area 1 but not in the area 0?.

Im using the area 1 filter-list prefix but i cant do it.

ESPAÑOL:

Bueno mi problema es que no puedo distribuir una routa por defecto en una sola area especifica y solo en esa area, e usado diversos comandos que permiten filtrar lo que va a ingresar a mi tabla de rutas o como es el caso de filter-list con la ayuda de area 1 solo puedo filtrar las rutas q se anuncian pero no una ruta por defecto, e intentado tambien usando el comando default-information originate con route-maps y access-list pero solo con eso solo he podido limita la redistribucion a todas las areas q tengo anexadas en base a si existe o no una ruta determinada en mi tabla. espero puedan ayudarme muchas gracias

4 ACCEPTED SOLUTIONS

Accepted Solutions
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Rising star

Hi,

Why don't you just make Area #1 as a totally stub-area? By this way all default route on routers in area 1 will point to ABR.

But make sure that routers are configured in an area with the same stub are configuration.

Hope it will help.

Best regards,
Abzal

Best regards,
Abzal

View solution in original post

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Configuring area 1 as stub or as totally stub should have the ABR advertise a default route into area 1 but not into area 0.

HTH

Rick

Sent from Cisco Technical Support iPad App

HTH

Rick

View solution in original post

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Rising star

Hi,

It' possible by using command under ospf configuration default-information originate on ABR connected to area #1.

router ospf 1
default-information originate [always]

If ospf router has default route it will advertise into an area. Once the default route removed it will not advertise into area anymore. But using command with always keyword it will advertise even does not have one.

Is this ABR connected only to area #0 and #1? If so it should work.

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9f0.shtml

Sent from Cisco Technical Support Android App

Best regards,
Abzal

View solution in original post

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Engager

Hi Pablo,

The filter-list only works with LSA Type 3, you can't filter external routes.
Depending on your reqierements, you can do it also within a NSSA by the "area 1 nssa default-information originate" command.
Between regular areas you can't filter this way as far as I know.

Saludos
Rolf


Sent from Cisco Technical Support Android App

View solution in original post

7 REPLIES 7
Highlighted
Rising star

Hi,

Why don't you just make Area #1 as a totally stub-area? By this way all default route on routers in area 1 will point to ABR.

But make sure that routers are configured in an area with the same stub are configuration.

Hope it will help.

Best regards,
Abzal

Best regards,
Abzal

View solution in original post

Highlighted

Configuring area 1 as stub or as totally stub should have the ABR advertise a default route into area 1 but not into area 0.

HTH

Rick

Sent from Cisco Technical Support iPad App

HTH

Rick

View solution in original post

Highlighted

Thanks for the help Can you please tell if exist other way to do the same thing but whithout using a totally stub area or an stub area in the area1?! Configure the ABR router?!

I been traying whit the command :

#router ospf 1

# area 1 filter-list prefix

Or the only way to do that is whith an stub area o totaly stub area?!

Highlighted
Rising star

Hi,

It' possible by using command under ospf configuration default-information originate on ABR connected to area #1.

router ospf 1
default-information originate [always]

If ospf router has default route it will advertise into an area. Once the default route removed it will not advertise into area anymore. But using command with always keyword it will advertise even does not have one.

Is this ABR connected only to area #0 and #1? If so it should work.

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9f0.shtml

Sent from Cisco Technical Support Android App

Best regards,
Abzal

View solution in original post

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ok ok but if i have a default route in the ABR pointing to 192.168.1.2 but this interface not belong to OSPF network and i have subnet 172.16.1.0/24 in the area 1 and 172.16.0.0/24 in the area 0 Can i distribute the default route only in area 1 ?!

thanks !

Highlighted
Engager

Hi Pablo,

The filter-list only works with LSA Type 3, you can't filter external routes.
Depending on your reqierements, you can do it also within a NSSA by the "area 1 nssa default-information originate" command.
Between regular areas you can't filter this way as far as I know.

Saludos
Rolf


Sent from Cisco Technical Support Android App

View solution in original post

Highlighted

thanks men! only whith the LSA type 3 ok ok the default route is LSA type 5

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