YES!
netmask is just another way to say subnet mask. crazy but confusing.
Subnet Mask provides Network & Class Identificationfor an IP Address.
Smaller than 65.56.0.0/14. With just the IP, there is no way to know the netmask. We can see that Level 3 owns that address and their block is a /14. It could be a /30 with a gateway of 65.56.25.18. it could be a /29 with a gateway of 65.56.25.18-22. In short, there is no way to definitively know the netmask from the IP only.
Subnet mask defines our network bit . If we are using a single network then all computers should have same subnet mask as well as the ip address, that belongs to the same network id.
No. 192.168.12.1 - 192.168.12.254 is one subnet (assuming 255.255.255.0 subnet mask)
/24 in CIDR 255.255.255.0 in netmask.
If the other PC is on the same LAN segment then it will have the same subnet mask as yours. A subnet mask is the same for all subnets within a network so that will be the same as well. For other networks it isn't important to know what their subnet is. You could always ask the other user to find out that information if you needed to know.
No, all subnets must use the same subnet mask
The default subnet mask for this address - a class A address - is 255.0.0.0 (same as /8).
It does not require a subnet mask.
If this is a default subnet mask, then it would be a class C subnet mask. If you are subnetting a network and this is not the default subnet mask, then it could be either a class A or class B.
The default subnet mask has a standard size. The custom subnet mask allows you to make subnets that are smaller or larger than the default.
The correct term is subnet mask instead of subnet mass. A subnet mask separates an IP address into the host address and the network address. It is a 32-bit number that can mask an IP address.