We don't use Windows Authentication because most of our clients have external users, and getting Windows Authentication to work through a DMZ has been something most IT departments don't typically want to deal with. So, for standardization purposes, we make everyone use regular Laserfiche User accounts.

So are the external users using the Windows Client or the Web Client? If it's the Windows Client, are they connecting through a VPN?

External users use Web Access. Internal users use the Windows Client. But we don't want two different account types (makes user administration more difficult and internal processes more complex), so we usually end up making everyone use Laserfiche Accounts.