Look at the first octet value and check the corresponding range.
1-126 class A, subnet mask 255.0.0.0
128-191 class B, subnet mask 255.255.0.0
192-223 class C, subnet mask 255.255.255.0
That could be a default subnet mask for a class C network.A mask used to determine what subnet an IP address belongs to. An IP address has two components, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) represent the Class B network address, and the second two numbers (017.009) identify a particular host on this network.Subnetting enables the network administrator to further divide the host part of the address into two or more subnets. In this case, a part of the host address is reserved to identify the particular subnet.
The address you gave is not an IP address; it has the appearance of a subnet mask. It could be a class A or class B subnet mask.
In a Class A address, the default subnet mask is 255.0.0.0, allowing for a large number of hosts within a single network, but with 16 bits designated for the subnet ID, the subnet mask becomes 255.255.0.0. In contrast, a Class B address has a default subnet mask of 255.255.0.0, and with 8 bits for the subnet ID, the subnet mask would typically be 255.255.255.0. Thus, the key difference lies in the number of bits allocated for the subnet ID and the resulting subnet masks, affecting the number of available subnets and hosts per subnet.
Class A default is 255.0.0.0 Class B default is 255.255.0.0 Class C default is 255.255.255.0
The default subnet mask for this address - a class A address - is 255.0.0.0 (same as /8).
it is a class c address..so default subnet mask is 255.255.255.0 it is a private address...
255.255.0.0255.255.0.0 is the default for a class B address
A unicast address is a unique IP address assigned to a single network interface, allowing for one-to-one communication. In IPv4, an unicast address falls within the ranges of 0.0.0.0 to 223.255.255.255, excluding reserved addresses. With a default subnet mask, for example, a Class A address (1.0.0.0 to 126.255.255.255) has a default mask of 255.0.0.0, Class B (128.0.0.0 to 191.255.255.255) has 255.255.0.0, and Class C (192.0.0.0 to 223.255.255.255) has 255.255.255.0. Thus, any address within these ranges is considered a unicast address when using the corresponding default subnet mask.
172.16.0.0. The first ip address within this subnet is 172.16.0.1
The default subnet mask would be 255.255.0.0 for a class B address.
Since this is a Class C address, the default network mask is 255.255.255.0.Since this is a Class C address, the default network mask is 255.255.255.0.Since this is a Class C address, the default network mask is 255.255.255.0.Since this is a Class C address, the default network mask is 255.255.255.0.
Since 157.54.4.201 falls in the class B address range the default subnet mask would be: 255.255.0.0 128 - 191 is a class B address.