When opening Office 2010 documents such as Word and Excel using a VPN client, you will receive a warning on the menu bar which reads; ” Protected View This file originated from an Internet location and might be unsafe. Click for more details. Enable Editing”.
Microsoft has provided options to add trusted network locations within the trust center in Word, Excel, and other Office 2010 applications, which also requires checking “allow trusted Locations on my network”. However it does not accept using IP addresses such as \\192.168.123.123\ShareName. You can use the UNC path but that also requires proper name resolution be set up for DNS.
The simple solution is to simply make sure DNS is configured for the remote domain by adding the DNS suffix to the VPN/PPP network adapter. This allows you to open the documents located on the remote domain without the warning error, and without configuring Trusted Locations. To do so, view properties of the VPN virtual network adapter and under the DNS tab of the advanced TCP/IPv4 properties, add your internal remote domain, in the “DNS suffix for this connection” box, such as MyDomain.local.
Then connect to the remote resource using the UNC name such as \\ServerName\ShareName. If the client computer is a member of the domain it will immediately connect, if not you will be prompted for credentials
the first time you connect. For the user name use the format MyDomain\UserName. So long as the local
session is active you will not be prompted for credentials again, even if the VPN connection is disconnected and reconnected.