How to share internet from Ethernet over Wi-Fi?
Connect your laptop to your router with an ethernet cable. Now your laptop is connected to the internet. If you want to share the internet connection to your iPad connected via ad-hoc Wi-Fi, you must set your Wi-Fi property (TCP/IP), choose DHCP with Manual IP, something like 10.0.1.1 netmask 255.255.255.0. Set TCP/IP as above, open ad-hoc network, new devices connecting to the adhoc network should receive an IP address. Now when you use Internet Sharing, devices connecting (like your iPad) will receive an IP.