Exchange 2003 Outlook Web Access (OWA) or IIS redirecting problem part2

(I hope it is ok to repost this under this Exchange area, as I got incomplete answers under the windows networking section. Original post: http://www.experts-exchange.com/Networking/WinNT_Networking/Q_21609338.html)

We have several Exchange 2003 servers running on windows 2000 server.

ServerA is the main server that receives all inbound email. It sends to to serverB, serverC, serverD, etc. The problem is with serverB. It is the newest server, set up by someone who made a mistake or missed some step.

Normally, when we go to the public URL for ServerA, if your exchange account is on ServerC, ServerD, etc. it will automatically redirect you to their public URL. This is not happening for ServerB. Note that all of the servers are part of the same domain (or child domain).

When someone types in "http://servera.ourdomain.com"
if their exchange account is on serverc, it sends them to
"http://serverc.ourdomain.com"
but for serverb, it redirects them to:
"http://serverb.ourPRIVATEandLOCALdomain.com"
which obviously only works for people on the LAN, and not out in the world.

The only way serverb works correctly is if you type it in manually like this:
"http://serverb.ourdomain.com/exchange"
and you have to put the /exchange part.

How can I fix this? Is it a DNS, IIS, or Exchange problem?

And if they could get in with http://serverb.cajunusa.com instead of getting the under construction message I'd be in a better situation. If someone could tell me how to redirect it would really help.

We had looked at the front-end configuration possibility a little, but for other reasons it is not an option for us.

thanks,
C