bgp and nat

[limapo2012]

Hello all,

Some questions about the non-standard scheme with bgp and NAT..i would like to find out will this scheme work?The picture and description is from here http://www.yasith.info/2011/04/how-setup-bgp-multihomed-network.html (Multihoming scheme, BGP with Full View from 2 ISPs, Private AS, NAT on the client's router), but i would like to get the fault tolerance for my critical servers - DNS and mail. For example, additionally to that scheme, i will have two public IP blocks from ISPs - 1.1.x.x/27 (ISP1) and 2.2.x.x/27 (ISP2). I will have two DNS servers, on one of them will be IP from ISP1, on other - IP from ISP2. If I will advertise the subnet of 1.x.x/27 to ISP1 and the subnet of 2.2.x.x/27 to ISP2, can this scheme provide the availability of my DNS server if other ISP had fallen? On the client's router will be configured the static NAT...

thanks in advance

[CSCO11267120]

Yes it does. But you will need static NAT with route-map in order to translate IP correctly.

[limapo2012]

Hi,

thanks for your answer. Have you met actually this scheme previously, for example in production?

[CSCO11267120]

Not in production.

http://www.cisco.com/en/US/docs/ios/12_2t/12_2t4/feature/guide/ftnatrt.html

I believe this document describe the scenario exactly for your case.

[limapo2012]

Thanks, i see...

And how about bgp and static nat (with route-map) simultaneously, their interaction?

[CSCO11267120]

There is no interaction. Static NAT only translate your DNS server IP, BGP is using interface address to establish neighbor.

[limapo2012]

i am sorry for my incorrect question... I mean the work of the scheme as a whole, bgp and nat...

[CSCO11267120]

Yes, I believe it will be working well.