The whole WAN verses LAN setup is confusing. I guess the S3 is a router under the hood, instead of just a simple Ethernet endpoint.
I don't have my S3s yet and the manual is not very complete. Can you specify that the WAN connection is a DHCP client? I think that that would be selected under "Protocol" popup, which in the manual they show as "Static address".
Being able to use DHCP to specify the IP address would be helpful because initially I'll be setting these up at home, then moving them to a data center. It would be nice to just be able to just move these from LAN to LAN and have them work. I have access to both DHCP servers so I can configure static IPs in both LANs based on the S3's Ethernet MAC address.
The reason why I'm interested in all this rather than just waiting is because It's possible that the S3 units will arrive while I'm out of town. If that happens, I'm going to ask my son to set these up. I want to make the process as simple as possible, and DHCP will help with that.
Here is what it looks like, Very easy
Just do not edit or change LAN:
So all you have to do is uncheck the "Disable DHCP for this interface" checkbox under the DHCP Server? Or does that option create a DHCP server (which would make no sense, but neither does the whole router thing).