OSPF ABR Type 3 LSA Filtering on Cisco IOS

This topic is to discuss the following lesson:

Thank you Rene.

thank you Rene.

Hi Rene,
Is the prefix-list is included in the Routing manipulation or possible security such as access-list?
Is this material for CCNP or CCNA?

Ael Irsal

Hi Ael,

Prefix-lists are CCNP material, you won’t find them in the CCNA exam(s).


Hi Rene,

It would be very useful if you can include with simulation labs using packet tracer .
btw, thanks for your demonstration…


Hi Ruby,

It doesn’t matter much if you use packet tracer, gns3 or real routers. Some of the commands that I talk about might not be supported in packet tracer.

Hi sir !
I learned a lot from you I read your books about ccnp
I just want to ask if you will make a CCNA Security? Im planning to take it this year :slight_smile:

Thanks! I do have some plans for next year…so I’m afraid you’ll have to find another study book for the moment :slight_smile:

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Hi rene,

Is it possible to filter other protocol without using stub? If yes please let me know. By the way thanks for clear explanation on all topics

Hi Rene

Your material & teaching method is magical.

Thank you Shelendra :slight_smile:

I really appreciate this site!! Thank you for all what you have done on this site to make us network professionals!!

You are welcome and thank you for your kind words Easton!

Hi, Nice write up! I guess best way to understand inbound filter-list is to explain LSA Type 3 filtering in Area 0 i.e. BackBone area, where the LSA is filtered before the ABR translate it in to Summary for Area 0 but all other non-backbone areas gets the Type 3 LSA from the BackBone.

Thanks for the lessson.

Hi Rene

Hope u r doing well.

can you explain what is the difference between default information originate and default information originate always in OSPF ?

Hi Shinu,

I’m doing great, hope you as well. I wrote a post on the OSPF default route:

You need the “always” parameter if you don’t have a default route in the routing table of the router that is advertising.



Besides using a prefix-list can I use an access-list to match on the prefixes?

Thank you



I’m afraid not, the filter-list command only accepts a prefix-list.