Two options:
1. Configure your D-Link to assign a static IP address to the pcWRT (consult your D-Link manual)
2. Select “Static” for Internet connection from the pcWRT management console. For example, enter 192.168.2.2 for IP address, 255.255.255.0 for netmask, 192.168.2.1 for gateway, 1.1.1.1 for DNS. To avoid IP address conflicts, exclude 192.168.2.2 from the DHCP pool on the D-Link. Again, consult D-Link manual on how to change the DHCP range on the D-Link.