Dear all, I've read the doc below that I can use single network adapter mode in ISA Server 2004 to publish owa. http://support.microsoft.com/default.aspx?scid=kb;en-us;840471 Internet-->checkpoint firewall----Isa 2004 | | Internal Lan | | | OWA Ex Srv AD Does it work also when using Outlook 2003 over https through isa 2004 (single nic mod) to connect the owa server (front end) and then access exchange server (backend with mailbox). I'm not sure outlook 2003 over https can access mailbox through isa --> owa and then exchange server with mailbox or it must access the exchange backup server directly. Please clarity if you have idea. Many thanks for your help. Patrick