IPv4 Address Helper

Java applet to assist in IPv4 address calculations would appear here if browser enabled for Java.

The tool assists in calculating what are the valid addresses with an IPv4 subnet. To use the tool:

  1. Type an IPv4 host address in (followed) by the return key. The class of address with then be identified, and the default subnet mask for the address displayed.
  2. Use the Up and Down buttons to adjust the netmask. The subnet address and broadcast address for the host address are calculated, along with the lowest and highest valid host IP address on the subnet.