Hello Exchanger.. I have a access to my Outlook using my OWA via VPN Connection, I need to use now RPC over HTTP without VPN, but I need to know really the difference between them. regarding several factors: - Security - Speed - Recommendation - you can add any other factor here.... I hope I will get a quick answer so i can decide to use one of them. Thanks

Hi Maher, Some of points i would like to put here. Security: You must allow only port 443 through your firewall, because Outlook requests use HTTP over SSL. If you already use Outlook Web Access with SSL, Exchange ActiveSync with SSL, or Outlook Mobile Access with SSL, you do not have to open any additional ports from the Internet. Speed : Generally issue of password prompt may occure if you use VPN but it work fine in ROH in slow speed internet too. Recommendation:: There are several benefits to using RPC over HTTP to enable clients to access Microsoft Exchange Server, instead of using a virtual private network (VPN). The benefits are the following: You can use the same URL and namespace that you use for Microsoft Office Outlook Web Access for Exchange Server 2003, Exchange ActiveSync®, and Microsoft Outlook Mobile Access. You can use the same Secure Sockets Layer (SSL) server certificate that you use for Outlook Web Access, Exchange ActiveSync, and Outlook Mobile Access. No unauthenticated requests from Outlook can access Exchange servers. Clients must trust server certificates, and certificates must be valid. Anil

Some would argue that Outlook Anywhere is not as safe as OWA because the typical OA client is caching the mailbox on the local workstation. Note also that group policy objects can not be applied to a non-domain joined client to enforce any Outlook configuration settings. Other than that, I dont see any difference as far as speed or using OWA or a mobile client.