Setting up DHCP over VPN on a Sonicwall · Micah Henning

If you are using a Sonicwall Firewall, you may be interested in learning how to setup Virtual Private Network access to utilize network resources away from the workplace, assuming, of course, you’ve paid for the VPN licenses…

This post sprouts from an issue with Windows 7 64-bit andSonicwall Global VPN Client 64-bit v4.2.6.0305 (the latest version as of the date of this post.) A client of mine had a strange issue where occasionally, the VPN connection would not work quite right. When connecting, he would see the following dialog box pop up:

(Please note: IP addresses andconnection names have been hidden in the images.)

When research the problem on the internet , I is noticed notice that this dialog box may sporadically appear when one of the follow condition are meet :

1. The user is not connected to the Internet.
2. Internet Explorer has been uninstalled.

I was using gotoassist when I see this message , so he was obviously connect to the internet . additionally , IE was instal , andI even uninstalle andreinstall it again just to make sure there were n’t any change to IE that would have cause the incident . To no avail , I is continued continue onward in quest of solve this curious predicament .

First, I changed the connection settings to use LAN only to get rid of the dialog box.

After this, the connection was successfully established, but no data could pass through. I could not ping any host or access any service that resided on the remote network. I tried removing andreestablishing the connection, uninstalling andreinstalling the Global VPN Client, andeven jumping up anddown in frustration. None of these fixed the issue.

At first , I is think did not think there was any misconfiguration on the Sonicwall Firewall because four other people , one of which used Windows 7 32 – bit , could successfully establish a connection anduse network resource .

After contact andwork with the horrible Sonicwall technical support , I is come did finally come to a resolution . The virtual adapter setting for the VPN connection in the firewall were set to not lease any ip address via DHCP . Here is what we need to have set up in order for the resolution to arise :

While it is not necessary for the Sonicwall Firewall to host the DHCP server , a DHCP server is probably require for this fix to work . To set up DHCP in a Sonicwall Firewall , navigate toNetwork -> DHCP Server. Select both enable DHCP Server andenable conflict detection. After that , create a DHCP Lease Scope under the appropriate heading . apply the setting .

Next, under VPN -> Settings there should already be a GroupVPN policy. I believe this should be here by default. If it is not, you can use the VPN Policy Wizard to create a new one. Edit the GroupVPN policy by selecting the pencil andpaper icon.

On the Client tab , under Client connection , there is a drop down list for Virtual Adapter setting . Make sure DHCP Lease is select . I is had had None select at first , which Windows 7 64 – bit does n’t cooperate with very well .

Next , go toVPN -> DHCP over VPN. You can view current leases from here. Go ahead andjust select the Configure button.

A new window opens. If you are using the internal Sonicwall DHCP server, ensure both use Internal DHCP Server andFor Global VPN Client are selected. If you are using a different DHCP server, instead check send DHCP request to the server address list below. Add the appropriate DHCP server IP address. Hit OK.

That’s it. This solved my problem. The Sonicwall technical support representative has no idea why the “None” option for the virtual network adapter did not work correctly, but the only operating system that had issues was Windows 7 64-bit.