The Postini addition to Google Apps are fascinating.  It seems a bit
rushed and clunky and cartoonish in its implementation but I'm sure
that will be worked out in the formal Google re-branding.

My question is this:  I have successfully added sub-domains to my main
Organization with Postini and all my MX records for all domains now
reflect the Postini flavor.

It seems one would then be able to remove the domain aliases from the
GApps Dashboard/Domains because, as I understand it, those domain
aliases are there only for the MX records.  At least that appears to
be the point and purpose according to that Domains page in our
Dashboard.

With the Postini MX records in place, why do we need those domains
aliased in our Dashboard?

Beware!

If you delete a domain alias from your Dashboard -- even with your
Postini-MX records propagated -- people will get an error message that
their message to you was undeliverable even though the message was
delivered.  Here's an example of the error:

***

<da...@boles.com>: host bolesuniversity.com.s7a1.psmtp.com[64.18.6.14]

***

The workaround is to delete your Postini MX records in your DNS Zone
file and put them back to their original GApps MX values and then re-
add your Domain via your Dashboard, have it verified, and then go back
a second time to delete the GApps MX records and and then re-enter
your Postini-MX records to get it all working again.

My questions is this:  Is that an intuitive process for working with
MX records and are we require to leave those domain aliases in place
in our Dashboard even with Postini implemented?

Also -- is there a limit on the amount of Domain Aliases we can add on
the Postini side?

Thanks!

David W. Boles
Author of "Google Apps Administrator Guide"
http://bolesbooks.com/thomson/
http://BolesUniversity.com