The only thing that this matches to is the domain name that they will need to enter on the NetExtender client side.
Tell it the domain that you want to use.
If you need to use a signed certificate go to system / certificates and manage that there.
I also turn on LAN so that I can test it internally. No reason to have a VPN setup if you can’t connect to it from the WAN.
Be certain that the WAN interface is clicked so that it is green.
Login and browse to the SSL VPN / Server Settings page.
Create your users and give them proper access to the right devices on your network.
There are 3 basic tasks to create a SonicWall SSLVPN. You will see just between these two releases (5.8.1.13 and 5.9.0.0) there are a few differences. And since verions 5.8.1.13 is recent in my memory, I have notes for that version here too. So, while they are all similar, this tutorial was done using a SonicWall NSA 3500 running SonicOS Enhanced 5.9.0.0-91o. Each one is somewhat different as the SonicOS changes and the steps and location of items changes from release to release. There are several great tutorials out there on how to setup a SonicWall SSLVPN.