In this scenario, the hosts behind Site B are set to obtain IP addresses dynamically. The goal is to forward the DHCP requests from hosts behind Site B through the tunnel to the DHCP server behind Site A SonicWall. This configuration is different from the DHCP over VPN configuration in that Site A and Site B are to be on different subnets.
Note: The IP addresses used in this article are examples. Change it to the IP addresses used in your network.
Create an IP Helper DHCP policy in Site B SonicWall to forward DHCP requests to the server behind Site A SonicWall:
Login to the Site B SonicWall management GUI
Navigate to the Network > Address Objects page.
Create the following address object for the DHCP Server
Name: DHCP Server
Zone Assignment: VPN
IP Address: 10.10.10.254
Navigate to the Network > IP Helper page.
Enable check box IP Helper and click on Accept to save the changes.
Enable check box DHCP under Protocols.
Click on Add under Policies to create the following policy.
Protocol : DHCP
From ZONE: LAN
To: Select the address object of the DHCP server.
Click on OK to save.
From a host behind the Site B SonicWall do ipconfig/release and ipconfig/renew. Assuming the VPN tunnel is up, the host will be leased an IP address by the remote DHCP server. The IP Helper page will display the information under DHCP Relay Leases: