Can 10.190.X.X be subnetted? I realize this is a private, Class A network. Not real strong on subnetting, this was the network ID I was given to work with. Looking for maximun subnets, minimal hosts.

Thanks.

Its a ClassA subnetted as a ClassB
Maximum subnet, minimal hosts gives:
Netmask 255.255.255.254
=>
16384 net of 2 hosts

Use this for lazy people:
http://www.cotse.com/networkcalculator.html

So subnetting the CLASS A network as a CLASS B is not an issue? That is what I was trying to get straight in my head. I can increase the number of hosts and decrease the number of subnets just by backing down the 4th octet to 252 for example?

Thanks again.

I made an error, its 255.255.255.252
252 is :
11111100 , which leaves 00 for hosts (00,01,10,11). You remove 00 and 11 which are the entire network and broadcast so you have 2 machines per subnets
Then you want to have more hosts, you shift to the left
11111000
which is 248 (or /29 in cidr notation)
and gives you 000=3 bits = 8 machines -2 = 6

No its not a problem is CIDR routing. http://www.faqs.org/rfcs/rfc1519.html

The rfc you mention are the address that the internet global router (not your internal, local adress in rfc terminology) will not route. If they receive a packet for this adress (they don't have your netmask, they only look at the prefix:10), they thrash it. Its for security measures.

Thanks. I'll give it a try.

The "Class" of a network is just a convention. You can in reality subnet a network however you want as long as you are aware of the limitations. 10.0.0.0 is classically a Class A network and would be found with a 255.0.0.0 mask. However you can subnet it however you want as long as you remember that the first address is always the network identifier and the last is always the subnet broadcast address.

If you give 10.0.0.0 a class c mask or 255.255.255.0 then you have 65536 possible subnets of 10.x.x.x each with 256 addresses, but the .0 and .255 addresses are not usable as hosts.

This is why the 255.255.255.254 mask is never used as it gives two addresses, one network and one broadcast and nothing in between. Ooops. 255.255.255.252 gives two usable host addresses, hence why it is used for point-to-point WAN links.

Basically network 10.0.0.0 doesn't exist on the internet, you need to NAT out to the internet so you can pretty much please yourself as long as you maintian a consistent scheme within you network.

Thanks.

What I did was use 10.190.X.X network, with 255.255.252.0 subnet mask.

Gives me all of the SUBNETS and HOSTS I need. I kept thinking classful addressing vs. classless addressing. Thanks again to all..