The subnet mask - expressed in binary - starts with a number of ones, followed by zeros. If (for example) the subnet mask is 255.255.255.0, this can also be written as /24 - that means that the first 24 bits are ones. In this example, that means that the first 24 bits of the IP address (in this case, exactly 3 bytes) are shared by all devices in the same subnet. So, if your IP address is 200.3.85.7, and the subnet mask is 255.255.255.0, all other computers in the same subnet will also start with 200.3.85.
Because each IP defines certain subnet mask.
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.
This is a network address
The network address of an IPv4 address of 192.168.7.5 with a subnet mask of 255.255.255.0 would be 192.168.7.0. Remember that the subnet mask determines the network portion of the IP Address.
255.255.255.0
255.255.255.0
it is a class c address..so default subnet mask is 255.255.255.0 it is a private address...
The default subnet mask for this address - a class A address - is 255.0.0.0 (same as /8).
Subnet mask for the above is 255.0.0.0
if the ip address is 192.168.2.1 then the subnet mask should be 255.255.255.0
The default subnet mask would be 255.255.0.0 for a class B address.
There isn't just a single subnet mask that could be used for that address. The default subnet mask would be 255.0.0.0, but there could be others if the network is subnetted.