IP Address
DHCP assigns an IP address to the controller automatically on a network containing a DHCP Server (a router will typically have a built-in DHCP Server).
When Static is selected, options IP Address, Subnet Mask, Gateway must be entered.
IP Address: Configures the manual IP address of the controller for use on a LAN. The first three values must match other devices on the network (e.g., 192.1.0.x).
Subnet Mask: Subnet Mask determines the manual address mask used by the controller.
Gateway: Set this option to match the address of the router that connects the LAN to the Internet.
DNS Server (Domain Name System) is an Internet service that translates domain names into IP addresses. The IP address of a DNS is required if using NTP time server or SMTP email.