Network Models and Enterprise Protocols

A set of vocabulary flashcards based on lecture notes covering the OSI model layers, enterprise networking protocols such as SMB, SSH, RDP, DNS, and DHCP, and web protocols like HTTP/HTTPS.

OSI Model

A conceptual framework that divides network communication functions into $7$ layers to provide a universal language for computer networking.

Layer 7 – Application Layer

The layer where humans or software interact with the network, facilitating tasks like reading messages and file transfers via protocols like HTTP, FTP, and SMTP.

Layer 6 – Presentation Layer

The layer that translates or formats data based on accepted syntax, handling encryption, decryption, and data compression.

Layer 5 – Session Layer

The layer responsible for establishing, maintaining, and terminating communication sessions, as well as managing dialogue control and synchronization.

Layer 4 – Transport Layer

The layer that manages data transmission between devices, breaking data into segments and utilizing protocols such as TCP and UDP.

Layer 3 – Network Layer

The layer responsible for moving data through different networks by routing, assigning logical IP addresses, and packaging data into packets.

Layer 2 – Data Link Layer

The layer that handles data entry and exit from the physical link, packaging packets into frames and using MAC addresses for internal network communication.

Layer 1 - Physical Layer

The layer that transmits raw bits ($0$ and $1$) through physical media such as cables, switches, and radio waves.

Protocol

A set of rules used to format and process data, acting as a common language for computers to communicate regardless of differences in hardware or software.

SMB (Server Message Block)

A client-server communication protocol used for sharing access to files, printers, and other resources on a network.

SSH (Secure Socket Shell)

A protocol that allows network administrators to securely access a remote server over an unsecured network using encryption and public key cryptography.

Symmetric Encryption

An encryption method in SSH that uses the same secret key for both encryption and decryption by both the host and client.

Asymmetric Encryption

An encryption method using two different keys, a public key and a private key, primarily used during the SSH key exchange process.

Hashing

A one-way encryption method in SSH that creates a unique fixed-length value to verify the authenticity and integrity of messages via HMAC.

RDP (Remote Desktop Protocol)

A protocol used to allow users to remotely access computers and servers from any location, though it is often a target for ransomware and backdoor attacks.

ICMP (Internet Control Message Protocol)

An error-reporting protocol used by network devices to notify senders of transmission problems or to check connectivity using Echo Request and Reply.

Ping

A common command that uses ICMP Echo Request and Echo Reply messages to test the connectivity between two network devices.

DNS (Domain Name System)

A system that translates domain names like www.example.com into corresponding numerical IP addresses for network routing.

A Record

A basic DNS record type used to point a website name to a specific IPv4 address.

AAAA Record

A DNS record similar to an A Record, but specifically used to point to an IPv6 address.

MX Record

A DNS record that specifies the mail server responsible for receiving emails on behalf of a domain name.

DHCP (Dynamic Host Configuration Protocol)

A protocol that automatically assigns IP addresses, subnet masks, and default gateways to devices on a network to prevent IP conflicts.

HTTP (HyperText Transfer Protocol)

An application-layer protocol based on a request-response model used for exchanging hypermedia like text and images on the World Wide Web.

Stateless

A characteristic of HTTP where each request is executed independently without any link to previous requests.

HTTPS (HyperText Transfer Protocol Secure)

An advanced version of HTTP that uses SSL/TLS certificates to provide privacy, data integrity, and identification through encryption.

SSL Certificate

A digital document used by HTTPS to verify the server's identity and establish an encrypted connection using asymmetric keys.