I am having a problem with CAS/OWA proxy. I have an ISA 2006 serverwith anExchange 2007 OWA publishing ruleto the CAS server in site A. OWA for mailboxservers in site A work just fine.Site A CASserversare suppose to proxy requests to the CAS server in site B. However, whena user from site B tries to access their mailbox (after ISA form authentication)they receiveerror 403.4. The CAS server in site B has the internal address listed with the https:// prefix and IIS has "require secure" connection box checked. Internal directconnections the site "B" CAS/OWA also work fine (secured).Any ideas? Thanks, Jeremy

Hello Jeremy, Can you access SiteB's OWA from Site A withou problems? I mean connecting from Internet Explorer https://serverb/owa What is the value of InternalURL of the SiteB owa site? You can use get-owavirtualdirectory to get this information and check out the parameter InternalURL. How about the IIS log files on SiteB's CAS?

Yes. I can connect to serverb from site A without issue. https://khsd-mail12.kernhigh.org/owa I cannot connect to serverB from serverA. https://khsd-hub-02.kernhigh.org/owa to site "B" Internal URL for is https://khsd-mail12.kernhigh.org/owa IIS shows the following lines over and over again 2007-07-02 22:05:17 W3SVC1 172.25.0.17 GET /exchange - 80 - 10.100.0.121 Exchange-Server-Frontend-proxy/6.5+Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.2;+WOW64;+.NET+CLR+2.0.50727;+.NET+CLR+3.0.04506.30) 401 2 5 2007-07-02 22:24:54 W3SVC1 172.25.0.17 GET /owa/ping.owa - 443 KERNHSD\KHSD-HUB-02$ 10.100.0.121 OwaProxy 242 0 0 2007-07-02 22:24:54 W3SVC1 172.25.0.17 GET /OWA/Default.aspx - 443 KERNHSD\KHSD-HUB-02$ 10.100.0.121 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.2;+WOW64;+.NET+CLR+2.0.50727;+.NET+CLR+3.0.04506.30) 403 0 0

Hello Jeremy, Make sure that the serverA doesn't have Forms Based Authentication, only Integrated Authetnication enabled, ok? Let me know if it works as well for you.