Firs have to mention, I have working Proxy solution with CAS server on second AD site. So on Internet facing CAS server work proxy work. Now the second AD Site, has additional WAN connection. The logical solution in case of failure of WAN connection in the internet facing (Site A) CAS server, you have to reconfigure both CAS server in each site, so that CAS server in Site B, is now internet facing CAS server , and CAS server in Site A, receive proxy requests for users in Site A. Now I have decided, to set up second IIS site on CAS server for Site A and Site B. With different IP, that is not registered with DNS, but manually entered in to DNS server. Host name for WAN and LAN connections stayed the same, but only that is setup revers. SO additional to working CAS proxy from Site A to Site B, there would be working proxy from Site B to Site A, so that in case of WAN failure, I have to change DNS record for WAN CAS access from IP of WAN on site A to IP on WAN on site B. So do not have problem for manually making switch over between Site A to Site B. First problem, that has arisen is, when I setup new EWS virtual directory on second WEB site on CAS server, it is automatically bound with 127.0.0.1:80 and 127.0.0.1:443, which cause default web site to failed, because it listen to 127.0.0.1:80 and 127.0.0.1:443 Is these solution even possible.

Does the /EWS still use the 127.0.0.1 even if you edit the binding on both websites to use the specific IP addresses, instead of “All Unassigned”?James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Yes. I setup network card, as if you would set it up for Private network, no DNS registration and NO NetBIOS. I set-up new HTTPS web site, that has IP of that network card, and I bind certificate. When i setup second EWS it binds 127.0.0.1. If i remove 127.0.0.1 bindings, and than make some changes for EWS, it put bindings back. I will try to bind http and https site for IP, and see what happens.

Ok, please update if there's any further updateJames Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

I give up today. Problem escalated with errors like : ARNING: The cmdlet extension agent with the index 0 has thrown an exception in OnComplete(). The exception is: System.Net.WebException: The request failed with HTTP status 404: Not Found. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at Microsoft.Exchange.SoapWebClient.CustomSoapHttpClientProtocol.<>c__DisplayClass4.<Invoke>b__3() " I clean up system, and setup recommended Proxy solution. It would be fine, if Microsoft published supported exotic configuration, so someone does not go in to a hole, and ends up not supported. Now the only thing, that I do not understand in all these, why does Microsoft don’t setup Exchange CAS servers, the way, that I do not need to do local servers names, when requesting owa certificate. Without TMG or UAG its very big security issue.