Question : How do I configure OWA internal/external URL's?

I was wondering if anyone could help me configure Outlook 2010's OWA internal and external URL's?

I'm currently running Exchange 2000 and have my public DNS is:

mail.ourschool.org


On my new Exchange server (2010) the Internal URL defaults to: https://mail.ourschool.org/owa

To continue to access the new server from the same address externally is it simply a matter of putting http://mail.ourschool.org (or mail.ourschool.org/owa) in the External URL field?....or will I need additional DNS entries on our DNS server?

Just trying to get a grip on this before I try to migrate.  Any help you guys might be able to provide on this configuration would be greatly appreciated.

Thanks....
John

Answer : How do I configure OWA internal/external URL's?

setting the external URL will benfit only with multiple CAS server in regional office.
you need an external DNS entry that points to an IP that is NAt'd from the firewall to the CAS server