A VPN session is established successfully. The client can pass most traffic, but cannot download files across the VPN tunnel.
To resolve this issue, perform these steps:
For more information on lowering the MTU, refer to the Adjusting the MTU Value section of the Usage Notes section of the Release Notes for VPN Client for Windows, Release 3.5.4.
Note: For VPN Concentrator version 3.6, the MTU can be adjusted through the GUI.
For more information, refer to VPN 3000 Series Concentrator version 3.6.
To resolve this issue, reconfigure the server to not set the DF bit or clear the DF bit on Cisco routers and PIX Firewalls.
For more information on clearing the DF bit, refer to DF Bit Override Functionality with IPSec Tunnels.