Internet Connection Sharing (known as NAT) gives you the ability to share a single Internet connection to a number of machines on your network. Everyone will then be able to use the Internet at the same time.
Frequently Asked Questions<
Do you need extra IP addresses to do this?
No.
But is it preferred to have extra IP addresses?
It depends on exactly what you will be running but normally there will be no advantage in having more IPs. We will advise you on exactly what you require.
Does my ISP allow this?
It depends on your ISP, some do and some don't. Please check with your ISP.