Netmasks for dummies 3007

Oh my goodness! Thank you all for your responses.

Moe: 194.9.124.0 - 194.9.126.207 makes me laugh out loud! I'm barely understanding how it works within the same Clbutt C block, let alone transversing blocks! My fingers hurt from all the binary counting! :)

I don't even have a guess as to the answer. I started with, "Let's see, 255 + 255 + 207 = 717, drop the network and the broadcast addresses and get 715, or maybe it's 253 + 253 + 205 = 711 with ... aarrrggh!" and then I stopped.

I did find some netmask calculators online, notably one at www.softwareeffect.com-tools-netmask.html , but, like others, it demands to know the "length" of the netmask, and entering "8" (for the 8 addresses I want to filter) returns 255.0.0.0, which I think would contain way too many IPs.

Perhaps this is the key piece I am not understanding ... the "length" of the netmask. The same calculator returns 255.255.255.248 when I enter "29", per my original post, but how is this considered the "length" of the netmask? I want to filter 8 addresses, so isn't my "length" "8"? Obviously not. So what does "length" refer to?

I'm using (to get the darn thing done) a calculator at www.csc.fi-english-funet-calc-laskin2.html , which allows me to put in the first and last IPs in the range and spits out 3 versions of the notation:

In: 196.25.32.0-196.25.39.255 Out: 196.25.32.0-255.255.248.0 , 196.25.32.0-0.0.7.255 , 196.25.32.021

Using that illustration and the middle notation syntax, I'm going to guess that Moe's sample IP range would use a netmask of: 194.9.124.0-0.0.2.207 . Now THAT I can understand right away. If it makes no difference, I'd feel comfortable with using that notation syntax for all of my netmask needs.

It's become clear that I'll need to get into the IETF docs to really understand this. Love it. Thanks again, everyone. Also, thanks for the script, Dr. Dheeman. I'll give it a try, too.