Networking With SAPT-0x02: Basic Networking Terms

Network Interface Card
Some common port number and their service
Visual Representation of Client-Server Interaction
Peer-Peer Network

The Network Core

This defines the connection of different network segments together and process to show how packets are transmitted across the network.

  1. Circuit Switched Network: A dedicated channel has to be established before the call is made between users. The channel is reserved between the users till the connection is active. This is mainly used for real time services like voice communication etc. For one way communication one channel is allocated and for two way communication two channels are allocated.
  2. Packet Switched Network: It is not required to establish the connection initially. It is already available to use by users. One drawback is that if traffic increases then it will lead to congestion in the network, hence this is mainly used for non-real time services.
Difference between circuit switching & packet switching

Transmission Media

A transmission media can be defined as any medium that is used to carry information from a source to destination.

Different Transmission Media

Guided Media (Wired):

Guided media are those that provide a wired-channel from one device to another. There are three types of Guided Media.

Types of Guided Media
  1. Twisted Pair Cable: In this wires are separately insulated and then twisted together. It is widely used in different kinds of data and voice infrastructure. The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. There are two types of twisted pair cable.
Visual Representation of UTP & STP
Visual Representation of Coaxial Cable
Visual Representation of Fiber Optic Cable

Unguided Media:

Unguided media transmit electromagnetic waves without using a physical conductor. This is often referred to as wireless communication. There are three types of unguided media.

  1. Radio Wave: These work through omni-directional antennas and waves can penetrate through walls, also the sending and receiving antennas need not to be aligned. It is used for multicast communications, AM and FM radios and cordless phones use radio waves for transmission. Its frequency range is 3KHz to 1 GHz.
Visual Representation of Radio Waves
Visual Representation of Microwave

Network Devices

Repeater: This will repeat the signals from one port to another. n important point to be noted about repeaters is that they do not amplify the signal. When the signal becomes weak, they copy the signal bit by bit and regenerate it at the original strength. It is a 2 port device.


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Prajit Sindhkar

Prajit Sindhkar


I am a India Based Security Researcher, Bugcrowd Top 500 Hacker and Bug Bounty Leader of the BUGXS Community