RE: OT (sort of): Setting up an OWA server in a DM Z

  • From: "Kamire, Thomas" <Thomas.Kamire@xxxxxxxxxxxxxxxxx>
  • To: "'[ExchangeList]'" <exchangelist@xxxxxxxxxxxxx>
  • Date: Fri, 22 Apr 2005 08:57:15 +0300

I have asked this question before, Can I use the same configuration which
was used in Exchange 5.5 on the PIX 515 Firewall or I need to open more
port. Once I know the ports to open then I will just go ahead and configure
Exchange 2003 OWA on the DMZ. This is a question I tend to get that is not
being addressed my Microsoft the way the did with Exchange 5.5 OWA
configuration using Cisco PIX firewall.

I do believe that we need to know in order for guys to go ahead with
implementation. This will tend to make users abandon Hardware firewall and
concentrate on software firewall (ISA) which is not very secure in this age
of spyware.

Please if someone can help in addressing this we users of Cisco products
would be very happy.


-----Original Message-----
From: adrian bolzan [mailto:abolzan@xxxxxxxxxxxxxxxxxxxxxxxxx] 
Sent: Friday, April 22, 2005 6:04 AM
To: [ExchangeList]
Subject: [exchangelist] OT (sort of): Setting up an OWA server in a DMZ


This is sort of off-topic as I am stuck at setp 1 of building an OWA server.

I am trying to configure a new server to act as an OWA server.  It is
located in our DMZ.
We do not use ISA server...

IP address of 'OWA' server = IP address of Exchange server,
which is also a DC =

The way our firewall works is to set an alias on the DMZ interface, and use
IP address and Port forwarding.
The alias on the DMZ interface =

Thus, communications from the 'OWA' server to the exchange server is sent to, with IP address and port forwarding to

'OWA' server --> IP Alias on DMZ interface --> DC (with Exchange) --> -->

My first problem is that when I try to join the OWA server to the domain
across the firewall I receive an error stating that I am trying to connect
to a closed port (presumably on the exchange DC).  All of the appropriate
filters are in place on the firewall to allow the communication.  The closed
port is 138/UDP.  This suggests that I need to configure the DC to allow
connections from the DMZ subnet.

Any pointers on where I would find info on how to allow this communication
would be appreciated. 


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