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Community Member

How to establish BGP Neighbourship without receiving BGP routes ?

Hi All,

I would like to establish BGP Neighbourship between my internet router and ISP router.

However I would not like my internet router to receive millions of bgp routes from the ISP router but my inside users should access internet via my internet router.

Kindly suggest how to do it.

Regards,

Mitesh Manwatkar.

7 REPLIES
Cisco Employee

Hi Mitesh, You can ask your

Hi Mitesh,

 

You can ask your ISP to advertise just a default route. On your internet router apply inbound route-map as well to permit just default route.

 

-- Pls dont forget to rate helpful posts--

Regards,

Akash

Community Member

Hi,We are also having some

Hi,

We are also having some servers which must be reached by rest of the world on internet.

Will it help in such scenario?

Regards.

Cisco Employee

 You can advertise your all

 

You can advertise your all internal routes to ISP, so that outside world can reach to your internal servers ,that is for reverse traffic. But to reach internet you just need a default route. You can contact your ISP with this requirement, they will help you out.

 

 

Hall of Fame Super Gold

It may be helpful to remember

It may be helpful to remember that in BGP learning routes from a neighbor and advertising routes to the neighbor are separate operations and are controlled independently. As Akash has explained you can configure a route map or a distribute list to control what routes you learn from your neighbor and have no effect of what you advertise. Appropriate network statements or redistribute statements allow you to advertise routes to your neighbor and have no effect on what you learn from the neighbor.

 

HTH

 

Rick

Community Member

Hi,I would like to know the

Hi,

I would like to know the command which ISP would use to advertise default route towards my internet router.

Regards.

Hall of Fame Super Gold

Mitesh There are several

Mitesh

 

There are several commands which an ISP might use to advertise a default route to you.

- there is a command under router bgp of default-information originate which will generate a default route to be advertised to neighbors.

- there is a parameter of the neighbor command neighbor 1.1.1.1 default-originate  which will generate a default route for that specific neighbor.

- the ISP might use a network statement or use redistribution to include the default route to advertise to neighbors.

 

HTH

 

Rick

Super Bronze

DisclaimerThe Author of this

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Also depending on you setup with your ISP, you might not need BGP at all.  Sometimes the ISP will advertize your public IP space (i.e. you don't need to), and if they do, all you need is a default route out.

PS:

Also BTW, often for basic ISP connectivity, even when BGP peering with your ISP, the ISP will not send you any routes but a default (because with a single link, there's no need for them).

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