private ip addresses

You may use private IP addresses with any subnet mask of your own choosing. As you probably already know. 10.0.0.0, 172.16.0.0, and 192.168.0.0 are IP address networks reserved for privately addressed networks. Addresses assigned in these ranges should never be advertised to the public Internet (by say, a DNS server), nor should they ever be allowed into your network (normally they are filtered out by the routers on the Internet).

For example, for the 10.0.0.0 network you could assign a subnet mask of 255.0.0.0 ("normal" for this Class A address), or 255.255.0.0, 255.255.255.0, 255.255.252.0, etc. The entire network is "yours" to subnet as you wish.

Happy subnetting!
--Marty C.

1. If you have a close network (one that will NEVER access the internet) you can use any IP address you choose. However, this is not recommended because it goes against the standards which are in use today.

2. If your network will be on the internet and your ISP has given each of your computers a public IP address, you MUST use those addresses.

3. Most likely, you will have a local area network (LAN) which sits behind a modem or router. Your ISP has either given you a specific internet IP address (which must be used in your router or modem) OR your internet connection is dynamic. This means that the IP address used by the ISP for your connection will change. This is determined by the policies of your ISP. In this case, you should use one of the IP address ranges given in the first answer. These are IP's set aside for private network usage. You are free to use these in any manner you choose. Any IP set, any NetMask, etc. What happens is that your modem or router uses NAT (Network Address Translation). When one of your computers access the internet, the private IP you have assigned to it, will be translated into the Public IP address which is used for your ISP's internet connection.

Recommendation: For your LAN, use the private IP addresses given in the first answer.

You need to scan the Internet for simple IP explanations. The only thing I can say is that when you use a mask, all workstation on the same network must use the same mask. Subnet masks segment your IP addresses: all it does is tell your devices such as routers, how many addresses are in an IP range you choose, such as 10.0.0.0 255.0.0.0 equals 10.0.0.1-10.255.255.254, or 16,581,374 IP addresses

And 10.0.0.0 255.255.255.0 equals 10.0.0.1-10.0.0.254, or 254 IP addresses..