RE: Useing OWA internaly

  • From: "Chris Maher" <cmaher@xxxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Tue, 16 Aug 2005 21:44:47 -0400

Since I know relatively little about ISA 2004, I'm going to go out on a
limb here and make some assumptions (and hope it has nothing to do with

Assumption #1: I assume you're using a non-public Domain naming scheme
for your company's Active Directory Domain (ie: Using xyzcorp.local
instead of or something similar.  You want to http:// to instead of mail.xyzcorp.local/exchange, right?

Assumption #2: If the above scenario is similar to what you've got,
you're probably using someone else to host public DNS for your company's
domain name (ie: Network Solutions is hosting DNS for and,
of course, you've got a DNS server for Active Directory & xyzcorp.local.

If all of the above is correct, what I think you need to do is create a
forward lookup zone on your Active Directory DNS servers for your public
domain name.  That is, create a forward lookup zone on your Active
Directory DNS Servers for and add a corresponding A and MX
record for to have the private IP address of your mail
server.  You could make the DNS record a CNAME for
mail.xyzcorp.local if you want.  

The main problem with this is that you have double-maintenance whenever
you need to change any DNS information to make sure your internal DNS matches the zone information with whoever is hosting
your public DNS.

As for the RPC over HTTP question...the only ports you should need open
are tcp port 80 for http and if you want to use HTTPS, tcp port 443

Hope this helps.

-----Original Message-----
From: Falah [mailto:falah.ahmed@xxxxxxxxxxxx] 
Sent: Tuesday, August 16, 2005 7:48 PM
To: [ExchangeList]
Subject: [exchangelist] Useing OWA internaly

Hi all,
Recently we have upgrade our exchange to exchange 2003, we ahve now
end and backend servers. most of our users useing OWA. If they use it
outside our LAN useing they can access it
without any problems, but if they try to use the same URL to access it
from our lan they can't reach it. I know that they can use the backend
server URL, but this is not idle selution coz it is going to confuse the
users, i want them to use one URL from both side
( is that possible? we have ISA 2004 as

As a second issue could u please let me know which ports do I have to
on pix firewall to use RPC over HTTP.


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