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. > >
