Exchange 2010 - List of active Outlook Anywhere users

here you go....

https://www.experts-exchange.com/questions/28987410/Get-a-list-of-users-with-outlook-anywhere-enabled.html

Get-Mailbox -resultsize Unlimited | Get-CASMailbox  |select name, MAPIBlockOutlookRpcHttp

Thanks Scott.  In addition to seeing who has Outlook Anywhere, I was really looking for a list of users who are actively using Outlook Anywhere.

Take a look at the following article.  It may give you what you need in reference to RPC connections.

https://ingogegenwarth.wordpress.com/2015/01/16/how-many-users-are-connected-to-exchange-per-protocol/

Thanks all, by the way Outlook Anywhere is accessed externally only and the traffic first passes through ISA.  Anyone know of a quick way to filter Outlook Anywhere traffic via ISA?

Uou need to use log parser. Furthermore, below thread give you some more idea:
https://practical365.com/exchange-server/exchange-2010-mailbox-audit-logging/

Exchange 2010 to Exchange 2016 Migration:
http://expert-advice.org/exchange-server/exchange-2010-to-exchange-2016-migration/