Archive for the ‘Exchange Web Services’ Category

Proxying CAS HTTP Cross Forest availability requests

Some of you may want to configure Cross Forest availability with your CAS Servers, but don’t necessarily want to open additional paths through your firewalls or networks for the CAS Servers to be able to talk directly with one another.


In this case, if you have an HTTP Web Proxy (obviously we like to use ISA Server), you can configure the CAS Server to use this to proxy it’s SOAP requests for Free Busy and Autodiscover to the other forest.


Locate the following folders (actual path may vary if you changed the default install path of Exchange):


..\Program Files\Microsoft\Exchange Server\ClientAccess\exchweb\ews

..\Program Files\Microsoft\Exchange Server\ClientAccess\Autodiscover


You will find a web.config file in each of these, to which you will need to add the following section (to clarify, it is best placed directly after /<system.web>):


                usesystemdefault = “false”
                proxyaddress = “http://proxyserver/
                bypassonlocal = “true”
                <add address=”http://[a-z]+/.contoso/.com$” />


For more information, check out the following MSDN article:


Important parameters are:


Usesystemdefault -> set to false to be able to specify our own proxy settings

Proxyaddress -> Your HTTP Proxy (ISA Server)

Bypassonlocal -> This setting is important if you have more than 1 CAS Server internally, and if your Proxy Server can not proxy internal HTTP requests.

Bypasslist -> The list of addresses which should be bypassed as local addresses.


Following the changes in the web.config files, you should perform an IISRESET.


You CAS Server will now use your HTTP Proxy for HTTP requests such as Cross Forest Free busy lookups, Cross Forest Autodiscover etc.

If you did not configure bypass lists, it will be using the HTTP Proxy for all requests.


Please note that this is only for HTTPWebRequests ( that the CAS Server initiates (such as those SOAP Free Busy requests to other servers) rather than responses to OWA Clients.

Microsoft Exchange Web Services Managed API 1.0 Beta released

Yesterday the Exchange DEV Team announced the Release of the EWS Managed API Beta. Some basic documentation is available at the the MSDN Site for the Microsoft Exchange Web Services Managed API 1.0 Beta SDK April 2009. The main object of the API is the ExchangeService. In the Getting started section You can see a basic code example for sending an email. In the future we will hopefully see some more samples and interesting results for working with the new API. David Claux has written an introductory article for the classes and methods.

Currently I work on a customer workshop for an Introduction to Exchange Web Services and IT operational aspects (Troubleshooting, monitoring and the like) of them. So I thought, that the below very short and loose linklist can be benefitial (links open in new window):


  1. The Vista EWS Gadget (Download Link) – You can see Your inbox, calendar, tasks and read them.

  2. The Exchange Developer Center (You can use this as a starting link)

  3. The Exchange DEV Team Blog, already mentioned before (This is an alternative starting point.) 

  4. The book “Inside Microsoft Exchange 2007 Web Services” about EWS, which is currently probably the book about EWS

  5. Glens Exchange DEV Blog – Glen has written a helper class DLL EWSUTIL, which You can reference in Powershell for various things – Glen has samples for OWA modification, contacts, finding unused mailboxes, postings to Twitter etc. – go and have a look)

  6. MVP Henning Krauses blog (Henning maintains a project for simplyfying Exchange Push Notifications, where You get informed about what is going on in a folder and recently wrote a lot about EWS with interesting samples) .

Enjoy !