We have some remote sites connected by IPSEC site-to-site VPN. Users run Outlook 2007 connected to Exchange 2007 at the main site.

It is common for Outlook to go through periods of  losing and regaining connections: Outlook displays constantly connection messages. The error occurs on an intermittent basis and does not effect all users at the remote site, the problem usually disappears after a day. Users can get access to e-mails through OWA and this does not have the same outage errors.

Not sure if it is related to other traffic running over VPN link but I cannot find any obvious cause.

• Edited by Graham M T Tuesday, February 17, 2015 7:29 PM

This Exchange 2007 Essential Business Server (EBS), there is one mailbox server with 90 users. It has mailbox, hub and client access role. There is seperate Edge server.

I will check out RPC performance monitoring but the problem only affect users at remote sites. The domain controller role as set by EBS on mail server may be affecting the problem.