Just playing devil's advocate, So, I'll get a callback from my provider when my server is down... Unfortunately, that callback is POSTed to a server that is a

Just playing devil's advocate, So, I'll get a callback from my provider when my server is down... Unfortunately, that callback is POSTed to a server that is already running on my provider, so I never see it :) (Assuming that you mean that the callback is an external thing, i.e. provider -> customer. Also, I suppose I could host the callback receiving server on another provider. But I don't want to.)