Answer
GFI WebMonitor should be able to scan files received through Outlook Web Access (OWA), however some conditions apply:
- HTTPS inspection must be enabled and configured:
- GFI WebMonitor 2013 Standalone Proxy Version - under Settings tab > Proxy Settings > HTTP
- GFI WebMonitor 2015 and later Stand-alone Proxy Version - under Settings tab > Core Settings > HTTPS scanning
- GFI WebMonitor ISA / TMG Version (2012 & 2011) - Outgoing packet inspection must be configured in the Microsoft TMG console (this is not available in Microsoft ISA Server)
- It will only work when clients on the internal LAN are connecting to a Microsoft Exchange server across the internet OR if connecting to a Microsoft Exchange server on the local network, the connections must be going through GFI WebMonitor and they must be doing packet inspection.