Computer Network Tutorial

Introduction of Computer Network Types of Computer Network Network Topology Computer Networking Architecture Transmission Modes (Data Flow) Basic Networking Devices Integrate Services Digital Network (ISDN)


OSI Model TCP/IP Model

Physical Layer

Digital Transmission Analog Transmission Transmission Media Switching

Data Link Layer

Error detection and Error correction Data Link Control Multiple Access Aloha

Network Layer

Network Layer - Logical Address Address Mapping Unicast Routing Protocol

Transport Layer

Process to Process Delivery User Datagram Protocol Transmission Control Protocol Stream Control Transmission Protocol Session Layer and Presentation Layer

Application Layer

Domain Name System Application Protocol E-mail Cryptography


Classes of Routing Protocols Classification of Routing Algorithms Controlled Access Protocols in Computer Networks Differences between IPv4 and IPv6 Fixed and Flooding Routing Algorithms Advantages and Disadvantages of Fibre Optics Cable APIPA Difference between Active and Passive FTP Fiber Optics and its Types Method of Joining and Fusion of Fiber Optic Cable Define Framing in Computer Network Disadvantages of Computer Network Mesh Topology Diagram in Computer Network Ring Topology in Computer Network Star Topology in Computer Networks 4G Mobile Communication Technology Advantages and Disadvantages of LAN Advantages and Disadvantages of MAN Advantages and Disadvantages of WAN Application Layer in OSI Model Cyclic Redundancy Check Example Data link layer in OSI model Difference between Transport and Network Layer Hamming Code Example Network Layer in OSI Model Session Layer in OSI Model Transport Layer in OSI Model Two Port Network in Computer Networks Uses of Computer Networks What is Computer Network What is Framing in a Computer Network Advantages and Disadvantages of Bus Topology Difference between Star Topology and Bus Topology Subnetting in Computer Network Subnetting Questions and Answers What is Bus Topology What is Network Topology and Types in Computer Networks Access Control in Networking Basic Characteristics of Computer Network Benefits of SOCKS5 Proxy in Computer Networks Computer Network viva Questions Difference between BOOTP and RARP Difference Between Network Topologies and Network Protocols Difference between NFC and RFID Difference Between Point-to-Point Link and star Topology Network Differences Between MSS and MTU Differences Between Trunk Port and Access Port Different Modes of Communication in Computer Networks MIME Protocol in Computer Networks Modes of Communication in Computer Networks Network Attack in Computer Network Port Address in Networking Simplest Protocol in Computer Network Sliding Window Protocol in Computer Network Stop And Wait Protocol in Computer Networks TCP 3-Way Handshake Process in Computer Networks What is a Proxy Server What is APPN What is ICMP Protocol What is Point-to-Point Protocol What is Port Address in Networking What is the HDLC Protocol What is VRRP Protocol Difference Between Analog and Digital Signals Difference Between Hub and Repeater Difference between Repeater and Switch Difference Between Transparent Bridge and Source Routing Bridge Source Routing Bridge in Computer Networks Transparent Bridge in Computer Networks Transport Protocol in Computer Networks Types of CSMA in Computer Networks What is Wired and Wireless Networking Network Security in Computer Network Disadvantages of Extranet Difference Between TELNET and FTP Define Protocol in Computer Networks Guided Transmission Media in Computer Network What is a Gateway in a Computer Network IGMP in Computer Networks LAN Protocols in Computer Networks MAN Meaning in Computer Modulation Techniques in Computer Networks Switching in DCN TCP/IP Applications What is IGMP? What is Modem in Networking What is Non-Persistent CSMA Difference between Cell Splitting and Cell Sectoring Forouzen Computer Network Open Loop and Closed Loop Congestion Control Types of Cluster Computing WAP-Wireless Access Point What are the elements of the Transport Protocol Difference between Gateway and Switch Flow Control in Data Link Layer Body Area Network Flooding in Computer Network Token Ring in Computer Networks VoIP in Computer Networks What is Infrared Transmission Congestion Control Techniques Forward Error Correction (FEC) Switching Techniques What is Telnet in Computer Network What are the Types of IPv4 Addresses IEEE 802.6 (DQDB) IEEE 802.15.4 Technology What is HDLC (High-level Data Link Control)? What is SMS Hubbing in Telecom? Circuit Switching in Computer Networks Communication Satellites in Computer Networks Features of HTTP Protocol IMAP4 (Internet Message Access Protocol) Internet Services How to Set up a Wireless Router Internetwork Routing in Computer Networks Distributed Computing System Features of GSM The 802.11 MAC Sublayer Protocol What is IEEE 802.3? What are Hubs and Switches in Computer Networks? What is Modem in a Computer Network? What is multicasting in Computer Networks? GSM -The Mobile Station What is Network Server? Slotted Aloha in Computer Network What is Ethernet in Computer Networks What is Arpanet? Radio Access Network (RAN) TCP 3-Way Handshake Process PING SWEEP (ICMP SWEEP) Print Server Private IP Address Security Services in Computer Networks Protocol Data Unit (PDU) CSMA with Collision Avoidance (CSMA/CA) What is Gateway in Computer Network? Advantages of Networking Data Link Layer Design Issues DHCP in Computer Networks Internet Security Association and Key Management Protocol (ISAKMP) What is Switch Hub? Telnet Full form in Networking Multimedia Systems Quality of Service in Computer Networks What is Carrier Sense Multiple Access (CSMA)? What is Circuit Switching What is Duplex Network? What is Web Protocol Network LAN Technologies Classes in Computer Network Low-Density Parity Check (LDPC) Wireless Internet Service Providers(Wisps) What is Handshaking? Cache Server What Is WSN Network? Check Sum Error Detection Linear Bus Topology Functions of the Transport Layer Infrared Transmission in Computer Networks Digital Signal in Computer Network Digital Data Transmission in Computer Networks Define Checksum with Example Computer Network Security Requirements Brust Errors in Computer Network Back Side Bus (BSB) 2-Dimension Parity Check in Computer Network Router and Brouter Microwave Transmission in Computer Networks Magnetic Media in Computer Network A One-Bit Sliding Window Protocol CDMA-Near-Far Problem Reference Models in Computer Networks Uni-cast, Broadcast, and Multicast in Computer Networks Uses Of Bridges in Computer Networks What are Gateways in Computer Network?

APIPA: Automatic Private IP Addressing

What is APIPA?

APIPA stands for Automatic Private IP Addressing. It is a word used by Microsoft to describe address auto configuration, which enables a Local Area Network (LAN) computer to assign itself a distinctive IP address when Dynamic Host Configuration Protocol (DHCP) is not available. Employing the network management protocol known as DHCP, businesses can dynamically allocate IP addresses and other network settings to devices or nodes on their networks. The necessity to manually assign IP addresses to the controlled devices is removed by DHCP-based services, which automatically manage client network configurations from a central server.

Small businesses to large enterprises all can use DHCP to support their various network sizes. When DHCP servers are down, DHCP clients can still get IP addresses thanks to APIPA. Except for Windows NT, APIPA is present in all current versions of Windows. Unless the Registry of the computer is changed to disable it, it is enabled on all Windows DHCP clients. Additionally, network adapters can be configured to support APIPA. It is also known as Auto-IP, Auto-Net, or DHCP failover method (for local networks).

Since Windows 98 and Windows ME, Dynamic Host Configuration Protocol clients have had access to Automatic Private IP Addressing (APIPA), which allows them to dynamically assign IP addresses to themselves in the absence of a DHCP server. APIPA facilitates the configuration and maintenance of small LANs and acts as a DHCP server failover mechanism.

History of APIPA

Initially, the IPv4 address block ( - has been set aside by the Internet Engineering Task Force (IETF) for link-local addressing. Traffic overload increases because of the simultaneous use of IPv4 addresses with various scopes. The link-local addresses are assigned to interfaces and are stateless in nature, allowing for the establishment of connection even in the absence of a response from the DHCP server. The address autoconfiguration technique is thus referred to by Microsoft as "Automatic Private IP Addressing (APIPA)".

How does APIPA work?

A DHCP client computer tries to contact a DHCP server whenever it connects to the network. If a server is available, it will give the DHCP client an IP address and other network information. A DHCP server might not be available in some circumstances. For instance, the server can be momentarily unavailable, or the network might not have any DHCP servers.

When this happens and APIPA is turned on, the client computer chooses an IP address from a list of predetermined addresses (ranging from to and assigns it to itself automatically. To avoid conflicts with DHCP routable addresses, the Internet Assigned Numbers Authority (IANA) allocates these addresses expressly for APIPA use cases.

The DHCP client employs the Address Resolution Protocol (ARP) as part of the APIPA assignment procedure to make sure the selected address isn't already in use by another network computer. Once the client has issued itself an IP address, it can communicate with other computers on the LAN using TCP/IP with a subnet mask of that are either manually configured for APIPA or with the correct address range.

Advantages of APIPA

  • Even if the DCHP client has previously got an IP address from the DHCP server, using the APIPA service can be advantageous.
  • This is accurate even if the lease at that address has already run out.
  • A DHCP client usually notifies the user when it switches between DHCP and APIPA addressing.
  • In some circumstances, depending on the OS and how the DHCP client is set up, APIPA can be disabled even though it is enabled by default.
  • Because APIPA may allocate IP addresses to networking hosts if DHCP fails, it can be used as a backup for DHCP.
  • Inappropriate broadcasting is stopped.
  • ARP (Address Resolution Protocol) is used to verify that the address isn't already in use.

Disadvantages of APIPA

  • The network can be slowed down by APIPA IP addresses.
  • Unlike DHCP, APIPA does not have a network gateway.
  • Use of APIPA addresses in local area networks is restricted.
  • Devices with APIPA configuration adhere to the peer-to-peer communication rule.
  • It adheres to the peer-to-peer communication norm and only allows usage of the addresses within the local area network.

Characteristics of APIPA

  • In the event of a DHCP server failure, APIPA establishes correct connectivity.
  • The primary DHCP server's response and status are controlled by APIPA for a predetermined amount of time.