Setting up subnets

The Subnet Calculator Interface

The Subnet Calculator:

simplifies calculating subnets and host ranges from a top-level address and a network mask length. These are obtained from your Internet Service Provider (ISP) or from a Network Information Center (NIC). The subnet mask length may be used to assign subnets to the top-level address.
speeds calculating subnets and host ranges. Working out subnets manually is time consuming.
calculates subnets without errors. Performing subnet calculations manually is susceptible to common mathematical mistakes, especially in conversions between binary and decimal numbers.
demonstrates the principles of subnetting. Use the Subnet Calculator to validate your own IP subnetting calculations.

NOTE: The Subnet Calculator should be used for calculation only. It does not implement the limitations and rules imposed by various RFCs. For practical purposes, you must understand these limitations and rules. For example, the network 10/8 should not be advertised on the Internet and should only be used internally, however the Subnet Calculator does not distinguish this network address from others. For details on what addresses are available, see ``Network address''.

You can start the Subnet Calculator in any of these ways:

Choose SCOadmin from the SCO menu (above the SCO logo) on the CDE desktop, and then select Networking Tools Subnet Calculator.
Start the SCOadmin launcher by entering scoadmin on the command line, and then selecting Networking Tools Subnet Calculator.
Enter scoadmin subnet calculator on the command line (or abbreviate to scoadmin subnet).

For more information on SCOadmin managers, see ``Administering your system with SCOadmin''.

Depending on the selection made in the Subnet Calculator, the main screen displays network address, network address length, subnet address, subnet address length, number of hosts, host ranges, netmask, broadcast address and comments. Use View Expand to examine the complete details for a selected entry in the list, and View Collapse to display the network address, network address length and comment. You can also expand and collapse individual entries by double-clicking on them. You can expand and collapse all entries by selecting View Expand All and View Collapse All.

You can perform many tasks by using the shortcut buttons located under the menu bar. The purpose of these is explained by the point help.

With the Subnet Calculator you can perform the following tasks:

Create a top-level address.
Add subnets to top-level addresses. You can also divide an existing subnet into further subnets, also known as variable length subnetting.
Add hosts to a subnet.
Add and modify comments.
Remove host entries.
Delete subnet entries.
Delete top-level addresses.
Print reports and save reports for later use in TCL or Perl scripts.