If you are using the SonicWall’s internal DHCP server
Check if the DHCP server has a range big enough to accommodate all clients.
If you’re using a Windows DHCP server
Make sure to check that the pool is big enough to accommodate all the users.
ESP Traffic is Blocked SonicWall GVC may be run from behind a firewall or other device that allows ISAKMP traffic to pass through, but does not allow ESP traffic to pass through. The DHCP requests that get sent for the virtual adapter are sent down the tunnel like any other traffic and are thus encapsulated in ESP. The ESP packets are simply dropped by the firewall with no indication back to GVC. To work around this problem, GVC is enabled to detect a NAT device in the middle. When GVC detects a NAT device, it encapsulates all ESP traffic (including DHCP packets) using the UDP header. The UDP header uses the same port as ISAKMP control traffic. Therefore the Peer must separate the IKE control traffic from the data traffic.
To configure the NAT traversal setting from the client, select the Connection in GVC and then select File|Properties. Select the Peers tab and then select the appropriate peer (head-end firewall) and choose Edit. Next choose NAT Traversal and select Forced On.
NAT Traversal UDP Encapsulated ESP traffic is blocked Occasionally GVC may be run from behind a NAT device that improperly handles NAT traversal packets (ESP packets encapsulated in ISAKMP). These packets are discarded by the NAT device without any notification sent back to GVC. To work around this problem, set GVC never to perform NAT traversal. This means that ESP traffic will not be encapsulated in UDP. In order for this to work, the NAT device must be in IPSec pass-through mode. This mode will prevent multiple GVC clients running simultaneously behind a single NAT device.
To disable NAT traversal in the client, select the Connection in GVC and then select File -> Properties. Select the Peers tab and then select the appropriate peer (head-end firewall) and choose Edit. Next choose NAT Traversal and select Disabled.
Verify settings on the Workstation
Make sure that the SonicWall LAN subnet and workstation IP address are not in the same subnet.
Try disabling the firewall and antivirus applications on the workstation. If you are running a client-based software firewall on the Vista machine, check if the version is Vista compatible. If it is not, then upgrade to the latest version. If it does not work after the upgrade then add a rule to allow TCP/UDP port 67/68. If this does not fix the problem then go to step C. (Note: There were numerous problems reported with Norton Internet Security Suite. If you have this software installed then the final try is to uninstall Norton and reboot your computer and then try again).
Verify that no 3rd party IPSec VPN clients are installed on your computer. Uninstall any existing IPSec VPN clients (including GVC), reboot, and then install GVC again.
Make sure that the virtual adapter is not assigned with any static IP address.
Make sure that the UDP ports 500 and 4500 is opened on the upstream device / Router.
Verify DNE binding is enabled for the SonicWall Virtual Adapter. Go to Start->Control Panel->Network and Internet->Network and Sharing Center->Mange network connections page. Select SonicWall Virtual Adapter and right click on properties. On the properties page verify Deterministic Network Enhancer binding is enabled.
Wireless WLAN 4.10+ wireless network driver includes VLAN Priority Support which conflicts with getting a DHCP lease for the SonicWall Virtual Adapter. Check if VLAN Priority Support is enabled. If it is, disable it by performing the following steps:
Right-click My Computer on the desktop and click Properties.NOTE: If there is no My Computer icon on the desktop, click Startand right-click My Computer on the right column of the Start menu.
When the System Properties window appears, click the Hardwaretab and click Device Manager.
When the Device Manager window appears, click the <+> next toNetwork Adapters and double-click Wireless WLAN Adapter.
When the Wireless WLAN Adapter Properties window appears, click the Advanced tab.
Scroll down to VLAN Priority Support and click to highlight.
Select Disable from the drop-down menu under the Value: field.
Click OK to close the Wireless WLAN Adapter Properties window.
Click the X button in the upper right-hand corner of the Device Manager window to close it.
Setting on the SonicWall virtual NIC Static IP.
To do this you will need to go into:
Network and sharing centre .
Change adapter settings
Select SonicWall VPN connection
Go to properties select IPv4 and put in an unused IP from the your ip pool.
If the client connects, with no issue after adding a static IP you are left with a couple of options.
Export the settings, make a backup.
Boot device into safe mode.
Factory default settings to the current firmware.
If you have an unassigned interface you can create and new IP range. EXAMPLE: 192.168.1.1 /24.
You will then need to add this to the DHCP server as a dynamic range.