Redirecting a domain when the server is down, possible?

[patents]

I want to set it up so that when the tommy is down, my main domain will redirect to another url. Then, when the server comes back up, it directs back to server tommy.

 

Is that possible? If so, how do I set that up?

 

Thanks in advance!

[Bailey]

Probably through a cached file but the visitor must have visited before.

[Luigi123]

Moved to Questions.

[Krydos]

You could do it if you hosted your own dns server, and when Tommy was down the A record changed to another IP. You'd have to set the cache fairly short though otherwise people would just continue to use the cached Tommy IP during the downtime. Short cache means the dns server would generate really high load.