Scenario:

Downloaded Sonicwall Firewall (multiple versions 4.10.2.0428, 4.10.1.0317, 4.9.22.0822, 4.9.14.0427, 4.9.9.1016) and tried one at a time. The connection is solid. The client connects to the home office just fine, you CAN ping resources via IP, but you CAN’T browse to intranet site although you can ping it.

Trying to navigate to an intranet site using Chrome or Internet Explorer, you’d get the following error:

After spending countless hours troubleshooting in the wrong direction, the simple and only resolution was to enable Jumbo Frame for the NIC card in use. 

Here’s how…

1. Open ‘Network and Sharing Center‘ – (you can type that in the start menu)
   
2. Click ‘Change adapter settings’ from the left pane
3. Right-click the NIC for which you want to enable jumbo frames and select ‘Properties‘.
   
4. Click on ‘Configure‘ Under the Networking tab
   
5. Click on the ‘Advanced‘ tab
6. Select Jumbo Frame on the left and change the value from disabled to the desired value, I put mine at 9kB MTU
   
7. Then click ‘OK‘

That’s all!

EDIT: This issue is caused by Sonicwall’s Global VPN client not playing nicely with certain ethernet drivers, namely intel and realtek. The above solution might work, however experience says that it does not more often than it does. A workaround for this issue is to install an external wireless adapter or network card that requires different drivers, preferably onces that play nicely with Sonicwall’s garbage VPN client.