Re: ISP inbound failover without BGP

[Randy Carpenter <rcarpen () network1 net>]

Is there some technical reason that BGP is not an option? You could allow them to announce their AT&T space via you as 
a secondary.

-Randy

----- Original Message -----
> This may sound like dumb question, but... I'm used to asking those.
>
> Here's the scenario
>
> Another ISP, say AT&T, is the primary ISP for a customer.
>
> Customer has publicly accessible servers in their office, using the AT&T
> address space.
>
> I am the customer's secondary ISP.
>
> Now, if AT&T link fails, I can provide the customer outbound Internet access
> fairly easily.  So they can surf and get to the Internet.
>
> What about the publicly accessible servers that have AT&T addresses, though?
>
> One thought I had was having them use Dynamic DNS service.
>
> Are there any other solutions, short of using BGP multihoming and having them
> try to get their own ASN and IPv4 /24 block?
>
>
> It looks like a few router manufacturers have devices that might work, but it
> looks like a short DNS TTL (or Dynamic DNS) needs to be set so when the
> primary ISP fails, the secondary ISP address is advertised.