We are using a Netgear VPN Firewall Router FVS318v3.. We have a DSL connection here at the office, and my users complain of the connection dropping, or locking up on their end.. Latest firmware is installed, rebooting the router doesn't help, no other internet connectivity issues reported anywhere else (ie., no other internet connection problems here, or at their end, except when connecting to the VPN..)

Is there anything else I can check to pinpoint this problem? TIA!!!