If you are already forwarding HTTP or HTTPS to an internal server and you only have a single public IP address, you need to select different (unique) ports of operation for either the existing servers or for the SMA appliance, because both cannot concurrently use the same IP address and port combinations.
To allow a WAN to DMZ connection
Using SonicOS, log into your gateway appliance as an administrator and click the Wizards icon at the top right of the interface.
On the Configuration Guide page, select the Public Server Guide, and then click Next.
On the Public Server Guide page of the Wizard, select:
Create new group
The Service Group dialog box is displayed.
In the Service Group dialog box, create a service group for HTTP and HTTPS:
Enter a Name for the service group.
Select both HTTP and HTTPS and click the arrow button to move to the right column.
On the Server Private Network Configuration page, enter the following server information and click Next:
Name for the SMA appliance
Server Private IP Address
The X0 IP address of the SMA appliance within your DMZ range,
such as 10.1.1.10/24.
Brief description of the server
On the Server Public Information page, accept the default IP address or enter a new IP address in your allowed public IP range. Click Next.
The default IP address is the WAN IP address of your SonicWall firewall. If you accept this default, all HTTP and HTTPS traffic to this IP address is routed to your SMA appliance.
The Public Server Configuration Summary page displays all configuration actions that are performed. Click Apply to create the configuration and allow access from the WAN to the SMA appliance on the DMZ.