Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a possible disaster recovery scenario, use a production server with public IP from AT&T, the disaster recovery server should have the same public IP but with a different ISP (Time Warner or Verizon).

Can this be accomplished and if so what do I need to do or have done at the ISP level?

share|improve this question

No, this cannot be done. At best, there would be a routing conflict and some people would go to the main server and some people would go to the recovery server.

Either way, if AT&T owns a particular public IP, nobody else is allowed to broadcast it as theirs, so even if your main server goes down and "stops using" the IP, another ISP cannot claim the IP and give it to your recovery server.

You need to use DNS to handle this kind of failover, where your DNS entries have a low TTL and update when the main server goes down to change to the recovery server's IP.

share|improve this answer
If you own a particular public IP range, though, you would be to "broadcast" it from multiple locations. Although I seem to remember one needs at least a /24, which wouldn't be easy to get even for a business. – grawity Oct 11 '12 at 19:59
@grawity That is multiple routes pointing to one location, which is different from multiple routes pointing to multiple, different locations. – Darth Android Oct 11 '12 at 20:22
This can be done with one or more VPNs. You can have the same physical endpoint device reachable on the same public IP address through links to different providers. However, you will still have a single point of failure -- the VPN endpoint that owns the single public IP address. (You might be able to find a provider that offers a fault-tolerant VPN that can end at different POPs.) – David Schwartz Feb 4 at 19:39

It's not impossible but it's pretty complicated. You want to investigate multi-homing. Here's a long presentation I found discussing multi-homing you might want to take a look at, but I think it's probably too complicated for an answer here.

Check out

share|improve this answer

Yes you can, We are doing this right now for our DR and we are AS-Path-Prepending our public route with "x2" prepends out DR. BGP is vector based and will choose the less aspath hop 3rd.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .