I have 2 RAQ4 (r and i). I have the RAQ4r running as a primary and the RAQ4i as a backup.

How do I get the email to queue up in the RAQ4i if the RAQ4r is down?

DNS now:
MX domain.com [20] --> raq4r.domain.com
MX domain.com [30] --> raq4i.domain.com

On RAQ4i, I have relay for domain.com.

Will the above work?
Say that joe@domain.com exist only on RAQ4r and it goes down (:bawling:) then I assume the email goes to RAQ4i. User (joe) does not exist on RAQ4i. Will RAQ4i place email in queue until RAQ4r comes backup?

Anyone got a better solution?

The solution you mention should almost certainly work.

Do not add whatever.com to class w or sendmail.cw on your machine!

Drew

What's class W or sendmail.cf?

I don't think so...
On the RaQ4i, it will go to the Catch-all account...

If the domain is not SETUP on the secondary, then it won't hit a catch-all.

Drew