Backup WAN... how did you resolve dns issue?

[mikearama]

Hey techies.

We have an ISP that continues to let us down, so I've been asked to investigate adding a backup ISP to the mix.

The issue that I forsee is that we host our own sites.

So picture this... ISP A drops the ball again, and our sites disappear to the public.

The border router detects the fault (via keepalive failure) and switches to the backup isp. The backup isp has assigned us another 27 IP's from their range, but the public will continue to resolve the old and now wrong IP's.

Those of you who have this kind of setup... how do you get around the dns issue and force dns convergence in a hurry?

Thanks for any insights,
Mike

 

[Alterac]

To do it right you need your own block of IPS, and an ASN number, run BGP on the outside (in co-operation with both your isps) and run HSRP/VRRP with another routing protocol on the inside. (Unless your using a single router).

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Bill

 

[Alterac]

Here are a couple articles

Basically you buy your own /24 block of IP's and advertise them to the world using your router, which is connected to 2 ISPS and using BGP routing.

ASN Numbers

http://en.wikipedia.org/wiki/Autonomous_system_(Internet)

BGP on Cisco Dual ISP:

http://articles.techrepublic.com.com/5100-10878_11-1039765.html

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Bill