Network

Background and History of Subnet Masks Subnet masks were formally introduced to the TCP/IP protocol stack in RFC 950 in 1985 to address the inefficiency of the early internet’s classful addressing system. In the early 1980s, the internet relied on Class A, B, and C networks. Class A used first-octet values from 1 to 126 and supported roughly 16 million hosts, Class B used 128 to 191 and supported about 65,000 hosts, and Class C used 192 to 223 and supported 254 hosts. ...

Background and History of CIDR CIDR (Classless Inter-Domain Routing) was introduced by the IETF in 1993 through RFC 1517, RFC 1518, and RFC 1519. It later became the internet routing standard with the publication of RFC 2050 in 1998. It was created to address two major problems in the older class-based IP allocation model. First, Class C networks with 254 hosts were often too small, while Class B networks with 65,534 hosts were far too large, which led to heavy address waste. Second, internet routing tables were growing rapidly and putting pressure on router memory and processing capacity. ...

What is Classful Addressing Classful Addressing is an IP address allocation method officially introduced in 1981 through the IETF’s RFC 791 document alongside the IPv4 protocol. It was designed to efficiently distribute address space and keep routing tables small on the early Internet. The system divides addresses into 5 classes (A, B, C, D, E) based on the bit pattern of the first octet (8 bits) of the IP address, providing different sizes of network address space for each class. ...

A static IP address is an IP address manually specified by a network administrator instead of being dynamically assigned from a DHCP server. It is essential in environments where the IP address must not change, such as server operation, remote access, and network service hosting. Ubuntu 24.04 LTS uses Netplan as the default network configuration tool and also supports nmcli and nmtui interfaces through NetworkManager, allowing users to configure networks in their preferred way. ...

Network switches emerged in the early 1990s to overcome the performance limitations of Ethernet networks. Unlike traditional hubs, which broadcast data to all ports, switches can forward frames selectively based on destination MAC addresses. That capability made them a core component of modern network infrastructure. In the OSI (Open Systems Interconnection) 7-layer model, switches are classified from L1 to L7 according to the layer at which they operate. Each type has distinct characteristics and purposes, analyzing protocol information at its respective layer to process traffic. ...

A socket is a software interface that abstracts network communication endpoints, first appearing in the 4.2BSD Unix operating system developed at UC Berkeley in 1983 and remaining a fundamental technology underlying internet communication to this day. It identifies unique communication points on a network through the combination of IP address and port number, providing a standardized API that enables data exchange between processes. History and Evolution of Sockets The Birth of Berkeley Sockets ...