Explorer or Netscape Navigator, you'll be able to use the calculators.
Netscape Navigator 4.0.x Users: There is a known bug in Netscape Navigator 4.0.x which will cause you to see this message
if you have the local cache turned off.
For help with any of the calculators, click here. If you think the calculator is wrong because it shows the first and last ('all zeroes' and 'all ones') subnets as being available, click here for an explanation.