What is the default subnet mask for Class C private IPv4 addresses?

The default subnet mask for Class C private IPv4 addresses is indeed 255.255.255.0. Class C addresses are defined by their first three octets as being part of the network and the last octet for host addresses. In the case of private Class C addresses, the range is specifically from 192.168.0.0 to 192.168.255.255.

A subnet mask of 255.255.255.0 divides the IP address into 24 bits for the network part (the first three octets) and 8 bits for the host part (the last octet), which allows for a maximum of 256 IP addresses in this subnet. Out of these, two addresses are reserved: one for the network address and one for the broadcast address, leaving 254 usable IP addresses for hosts.

Understanding this mask is critical for configuring networks that utilize private IP space since it defines how devices communicate and how network traffic is managed. The choice of 255.255.255.0 thus aligns perfectly with the characteristics of Class C private address allocations.