Autodiscovery url for same domain users

Question

I am using EWS managed API to implement notification subscription with exchange server. So, I am trying to figure out if I can assume that the autodiscovery url for users within the same domain will be same?

Answer 1

Yes

Autodiscover is used to get necessary information on how to connect to the exchange server by itself, with minimal user input required. It does so by taking the domain from the users e-mail address and is testing various standard EWS Exchange-Endpoints with it.

An example:

"https://" + domain + "/autodiscover/autodiscover" + fileExtension

Because users within the same domain communicate with the same exchange server, the AutodiscoverURL stays the same for all of them.

Answer 2

You should be using Autodiscover to work out the endpoint for ever user unless you have a very simple network topology (eg one server etc) so making that assumption woudn't be best practice. The URL that Autodiscover will return can be different for a number of reasons eg different Internal and External exchange configuration https://technet.microsoft.com/en-us/library/hh529912(v=exchg.150).aspx (so depending on the client location). Also if your using notifications on Exchange 2013 and up for multiple users then you should be using Autodiscover to get the grouping information for the users https://msdn.microsoft.com/en-us/library/office/dn458789(v=exchg.150).aspx so you can maintain affinity correctly.