I am looking fora best practice for how often a third-party server application should perform autodiscover for Exchange users.For my server application that uses EWS, I implemented the Outlook algorithm for finding the EWS url for a given user using the EWS autodiscover service. My understanding is that everytime Outlook starts, it redoes the autodiscover process for the Outlook user. Is that correct? If so, if I have a server application that can have 10000s to 100000sof users, for each of those users how often should I requery the EWS URL for each user?Can I just persist the EWS URL in SQL Server for each useruntil specific C# exceptionsare thrownfrom the EWS API that will then tell me to requery the EWS url for the impacted users? If so, what exceptions would tell me that I should redo the autodiscover process for a specific user?Would reperforming the autodiscover process for all of my users every 6 to 12 hours be overkill and really make my Exchange and networkadmins unhappy? I'm also thinking about adding a configuration setting where I'll let the admins of my server application specify how often the autodiscover process should be reperformed.I'm new to EWS,and soI'mhopingthere are some best practices in this area, or at least some expert insight intohow to do this well or how other server applications handle this issue :)

Well, I'm no Web Services programmer, but as far as autodiscovery, I dont think autodiscoveryperformance is going to be a concern for you as long as the Exchange folks have correctly sized the Client Access Servers.

Dear,As you said "whenever outlook starts it checks for autodiscovery process for the outlook users" Well this is not correct.Autodiscover will only works in such conditions.1. When a new user account is configured or updated.2. When a user periodically checks for changes to the ExchangeWeb Services URLs.3. When underlying network connection changes occur in your Exchange messaging environment.For Refrence :http://technet.microsoft.com/en-us/library/bb124251.aspxThanks and Regards,Ashwini Kumar!!! Happy to Help !!!Know more about Messaging :-)