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Advertising /24 IP Prefix to internet

Our customer is connected to internet via a static route to ISP, now they want to advertise a subnet to internet, is it possible to do that, please help.
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Craig Beck
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Depends.

Do they have a public /24 to advertise?
Do they have their own ASN that the /24 is assigned to?
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Yes, they want to advt public /24 IP Address prefix.
Yes, they have their own ASN.
what kind of device is connected to the internet and does the bgp ?
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Customer Router <--Static Route ---> ISP Router <----> Internet cloud

I would think ISP Router would do the BGP
if you don't do the bgp advertisement. then you need to ask youre ISP to add the subnet to the router.
when it's advertised you can you it.
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Yes, that sounds like a workable way around, is there any downside to it?
They will do next-hop routing and be able to use the ip’s on youre local router. There will be no downtime to do this
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Ben;
I thought about it, can one use private range (inside) to public range range (outside) with NAT overloading to accomplish the same?
That is taking /24 10.0.0.0 range and having it NAT to 80.80.80.0 range outside to ISP Router.. Just a thought
What is there behind the isp router? A firewall ?
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You mean between Customer router and ISP router, I guess there nothing in between..
The Customer Router might be able to perfom NAT as requested. Of course that exposes the complete private network to the public, and so requires firewall rules to protect against unwanted traffic and attacks.
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Hi Ben;
We proposed to customer the solution involving our ISP Provider advt. their prefix at ISP end and
Customer came back , their concerns are follows:
1. Our internet is one of the two, first provider is connecting via BGP and we (second) would be connecting them via ISP for BGP. Would they be able to load share the traffic between the two links?
2. If our static link w/ ISP router goes down, and ISP Router is still announcing our paths for incoming traffic, how would this scenario get taken care of?

Please let us know if it is possible to take of above scenarios?

Thanks;
then both providers need to do bgp to the customer side. at the customer side the subnet will be advertised to the shortest path in the bgp (primair connection) and when this link fails the backup path will take over.

organise a conference call with both providers and ask them what both need to do. to build this.
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Vendor 1 <--BGP-- Customer Site---Static-->ISP Router---->Internet

Vendor 1 is connected via BGP,
The connection we are proving to customer is static to another provider, can customer do BGP for both providers at their router?
yes off cource, see the image below how the topology will look like

provider a will give you a /31 subnet and provider b will do the same.
they will advertise only the default route.

you will advertise the subnet. and do the path prepending to select a primair and backup path

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Ben;
Seem to me that it is primary/backup solution, will it do load sharing on two links originating from Customer Router? Your help is very much appreciated and beginning to see the light.
If you keep the path prepend the same it will do load ballancing. This is for outbound traffic. Inbound will go to the prefered lowest cost connection
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Thanks Ben,
I see your point now, the AS number would be the AS number of the ISP provider right?

Please let me know What other things does ISP Router need configured?
you will get a non registerd asn from the provider normaly in de range of 64512-65534 these are for private use.
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Ben;
The customer has its own Public ASN, so I guess we can use it instead of private range. Also, up above, I thought we should be using /30 IP Addresses for the 2 providers as x.x.x.x/30 and y.y.y.y/30??

Thanks again;
When they have there own asn. it is published on there router. it will make it easyer to make a redundant connection with a second provider.
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Ben;
Can you please explain the sentence below:

"provider a will give you a /31 subnet and provider b will do the same.
 they will advertise only the default route."

I think it should be prefix route instead of default route. Please let me know.

Thanks
Ravi
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Benjamin Van Ditmars
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Thanks Ben, appreciate your input.. your replies were very too the point and appropriate.
Youre welcome