Wireshark for Beginners

This section includes some concept required before starting the wireshark tutorial.

What is TCP/IP?

TCP/IP is a set of protocols (Protocol Suit) that enable communication between computers. Protocols are rules or standards that govern communications. If two devices in a network need to communicate, they need to use a common protocol.

OSI Layer

Open Systems Interconnection is a layered reference model followed by systems when communicating with each other in Network. It’s Seven layer structure where each trailing layer provide data to upper layer for processing.

Hubs, Switches, Routers

Hubs

Hubs are the common network devices used for LAN (Local Area Network) connectivity. Nowdays Network switches are replacing hubs. Hubs operates at First layer in OSI. When a hub receives a packet of data (an Ethernet frame) at one of its ports from a network device, it transmits (repeats) the packet to all of its ports to all of the other network devices.

Switches

Switch forwards the ethernet frame from one system to other system in network based on MAC address. Switches operates at Layer 2 in OSI Model.

3-Way Handshake

It’s a Method used by TCP/IP to establish the connection between Cliet and Server

1. CLient sends a SYN packet.
2. Server respnds back with SYN+ACK packet.
3. Client Acknowedges the SYN+ACK packet by sending ACK packet to server.

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