09-10-2014 09:24 PM - edited 03-04-2019 11:44 PM
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.
09-10-2014 10:46 PM
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
09-10-2014 10:53 PM
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.
09-10-2014 11:01 PM
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.
09-11-2014 05:09 AM
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
09-17-2014 04:51 AM
Hi,
I would like to know the command which ISP would use to advertise default route towards my internet router.
Regards.
09-17-2014 06:16 AM
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
09-11-2014 05:24 AM
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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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