ActiveSync is not affected by the issues we were seeing with other protocols, like IMAP. IMAP, XMPP, POP, SMTP all use our own TCP code to process requests. Requests from ActiveSync, EWS, WebDAV use web requests and thus IIS's pipeline for processing requests and thus are NOT affected by the issue Damir claims.
https://portal.smartertools.com/community/a91071/imap-problems-with-6816.aspx
Matt Petty
Senior Software Developer
SmarterTools Inc.
www.smartertools.com