Setting up secondary MX

[Kurt]

> I know how to setup the record priority and everything but I never could
> figure out how to make it "store and forward".  I have a setup where is host
> A is down all mail goes to host B, no problem there.  But, when host A comes
> back online I have to manually get the mail off host B, it does not get
> forwarded automatically once host A comes back on-line.

I believe host B has to be configured to watch for host A to come back up.
Are both A and B under your control?

--Kurt