Help Desk Prep

IP Address

A unique numerical address that identifies a device on a network so data knows where to go

DNS

Domain Name System; translates human-readable domain names like google.com into IP addresses

TCP

Transmission Control Protocol; a reliable, connection-oriented protocol that ensures data arrives in order and without errors

UDP

User Datagram Protocol; a fast, connectionless protocol that sends data without guaranteeing delivery or order

TCP vs UDP

TCP is reliable but slower; UDP is faster but less reliable

Default Gateway

The router or device that sends traffic from your local network to other networks or the internet

Local Traffic

Communication between devices on the same network that does not need to leave the local network

Internet Traffic

Communication with devices outside the local network that must go through the default gateway

TCP/IP Model

A networking model used to describe how data travels across networks

Application Layer

Top TCP/IP layer; provides services for applications like web browsers, email, and file transfers

Transport Layer

TCP/IP layer responsible for end-to-end communication using TCP or UDP

Internet Layer

TCP/IP layer responsible for logical addressing and routing using IP

Network Access Layer

Lowest TCP/IP layer; handles physical transmission of data over cables, Wi-Fi, and hardware

HTTP

Hypertext Transfer Protocol; used for web communication

HTTPS

Secure version of HTTP that encrypts communication

FTP

File Transfer Protocol; used to transfer files between systems

SMTP

Simple Mail Transfer Protocol; used for sending email

DNS Port

Uses port 53

HTTP Port

Uses port 80

HTTPS Port

Uses port 443

TCP

Commonly used for HTTP, HTTPS, FTP, SMTP because reliability matters

UDP

Commonly used for DNS, streaming, VoIP, gaming because speed matters

ping

Tests connectivity to another device; shows reachability, latency, and packet loss

tracert

Shows the path packets take to a destination; identifies hops and where connection fails

nslookup

Queries DNS to translate domain names to IP addresses; helps troubleshoot DNS issues

ipconfig

Displays network configuration including IP address, subnet mask, default gateway, and DNS servers

netstat

Displays active network connections and listening ports

tasklist

Lists all currently running processes with PID and memory usage

sfc /scannow

Scans and repairs corrupted or missing Windows system files