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Networking

Networking Fundamentals — Zero to Advanced

From what a packet is to subnetting, routing, DNS, TCP, and firewalls — 35 live lessons, no prerequisites

Networking cheat sheet and project ideas →

Self-paced May 2026
🎓Complete beginners — no networking knowledge needed
🔐Security learners who need networking foundations
💼Anyone preparing for CompTIA Network+ or Security+
🖧Developers who want to understand what their code runs on
44
Lessons
7
Sections
364+
Topics covered
16h
Total content
100%
Free forever
This course builds the networking foundation every security professional needs. You will understand how packets move from your keyboard to a server on the other side of the planet — every hop, every protocol, every layer. Lesson 01 assumes zero prior knowledge. The live modules build from packets and layers through routing, transport protocols, application protocols, and network security.
What makes this different
◎
Built for Security
Every protocol is taught alongside how attackers abuse it — so you understand defence, not just theory.
▶
Real Commands
Wireshark captures, tcpdump filters, nmap scans — commands you run on your own machine as you read.
⊞
Packet-Level Diagrams
Every major protocol is shown as actual bytes — so the OSI model becomes concrete, not abstract.
≡
No Fluff
No "send us your email for a certificate". Just the concepts, explained clearly, from first principles to advanced.
→
Recommended next course after this one
Once you have finished the live modules here, you have the networking foundation needed for the Cybersecurity course.
Cybersecurity — Zero to Hired →
// Curriculum

35 Live Modules. Packets to Network Security.

Follow in order. Each module builds on the last. Lesson 01 assumes you know nothing — the advanced modules end with protocols and defenses used by professional network engineers and security researchers.

1
Section 1 — How Networks Work
MODULE 01✓ LIVE

What is a Network?

Packets, nodes, protocols — and what actually happens when you press Enter in a browser

PacketsNodesClients & serversProtocolsWhy networks exist
⏱ 18–24 min
Beginner
Start →
MODULE 02✓ LIVE

Network Types and Topologies

LAN, WAN, MAN — and why the physical layout of your network determines what can go wrong

LANWANMANStarMeshBusRingHybrid
⏱ 20–26 min
Beginner
Start →
MODULE 03✓ LIVE

The OSI Model — All 7 Layers

The universal framework every engineer uses to reason about networking problems

OSIPhysicalData LinkNetworkTransportSessionPresentationApplication
⏱ 22–30 min
Beginner
Start →
MODULE 04✓ LIVE

The TCP/IP Model — How the Internet Works

The four-layer model that actually runs the internet — full packet walk-through from click to server

TCP/IPLink layerInternet layerTransport layerApplication layerEncapsulation
⏱ 20–26 min
Beginner
Start →
MODULE 05✓ LIVE

Data Transmission — Signals, Bandwidth, and Latency

How bits travel as electrical signals, light, and radio waves — and why latency kills more apps than bandwidth

BandwidthLatencyThroughputJitterAnalog vs digitalEncodingNoise
⏱ 16–22 min
Beginner
Start →
MODULE 06✓ LIVE

Binary and Hexadecimal for Network Engineers

The two number systems that appear in every IP address, MAC address, and packet capture

BinaryHexadecimalDecimal conversionBits & bytesNibblesWhy networking uses hex
⏱ 14–20 min
Beginner
Start →
2
Section 2 — Physical and Data Link Layer
MODULE 07✓ LIVE

Cables, Connectors, and Physical Media

Cat5e vs Cat6A vs fiber — and why the cable you choose determines your ceiling

Cat5eCat6Cat6AFiberCoaxialRJ-45SFPPoETIA-568
⏱ 16–22 min
Beginner
Start →
MODULE 08✓ LIVE

Ethernet, Switches, and MAC Addresses

How devices on the same network find and talk to each other — frames, CAM tables, full duplex

EthernetFramesMAC addressSwitchCAM tableCSMA/CDFull duplexCollision domain
⏱ 20–26 min
Beginner
Start →
MODULE 09✓ LIVE

ARP — How IP Maps to MAC

The protocol that bridges Layer 3 addresses to Layer 2 — and how attackers exploit it

ARPARP cacheARP requestARP replyGratuitous ARPARP spoofingARP poisoning
⏱ 16–22 min
Beginner
Start →
MODULE 10✓ LIVE

VLANs — Network Segmentation Without Hardware

802.1Q tagging, trunk ports, inter-VLAN routing — and why VLANs are the first line of internal defence

VLAN802.1QTrunkAccess portNative VLANInter-VLAN routingVLAN hopping
⏱ 18–24 min
Beginner
Start →
MODULE 11✓ LIVE

Spanning Tree Protocol — Preventing Broadcast Storms

How STP stops switch loops from bringing down your entire network in under 1 second

STPRSTPRoot bridgePort statesBroadcast stormBPDUConvergencePVST
⏱ 18–24 min
Beginner
Start →
MODULE 12✓ LIVE

Wi-Fi — 802.11 Standards, WPA2, WPA3

2.4GHz vs 5GHz vs 6GHz, channel overlap, WPA3-SAE, and every way wireless gets attacked

802.11acWi-Fi 6WPA3SSIDChannelCSMA/CAEvil twinDeauthPMKID
⏱ 20–28 min
Beginner
Start →
3
Section 3 — The IP Layer — Addressing and Routing
MODULE 13✓ LIVE

IPv4 Addressing — Complete Guide

Public vs private, RFC 1918, CIDR notation, address anatomy — everything about the 32-bit address that finds every device

IPv432-bitDotted decimalPublic IPPrivate IPRFC 1918CIDRAddress classes
⏱ 18–26 min
Intermediate
Start →
MODULE 14✓ LIVE

Subnetting — Divide Any Network with Confidence

Subnet masks, network ID, host range, broadcast — the skill every network interview tests

Subnet maskNetwork IDHost rangeBroadcastCIDR/24/16/30VLSMFLSM
⏱ 24–32 min
Intermediate
Start →
MODULE 15✓ LIVE

IPv6 — The Protocol That Replaces IPv4

128-bit addressing, EUI-64, SLAAC, link-local, dual stack — and why you will manage both for the next decade

IPv6128-bitEUI-64SLAACLink-localGlobal unicastDual stackNDPDHCPv6
⏱ 18–26 min
Intermediate
Start →
MODULE 16✓ LIVE

Routing — How Packets Find Their Destination

Routing tables, default gateway, longest prefix match, TTL, how every hop decision is made

Routing tableDefault gatewayLongest prefix matchTTLHopStatic routeNext hop
⏱ 18–24 min
Intermediate
Start →
MODULE 17✓ LIVE

Dynamic Routing — OSPF, EIGRP, BGP

How routers learn paths automatically — link-state vs distance-vector, AS numbers, BGP hijacking

OSPFBGPEIGRPRIPLink-stateDistance-vectorAS numberBGP hijackingRoute redistribution
⏱ 20–28 min
Intermediate
Start →
MODULE 18✓ LIVE

NAT and DHCP — How Private Networks Work

How 4 billion private IPs share the internet — port mapping, DORA, lease times, starvation attacks

NATPATSNATDNATDHCPDORAIP leaseDHCP starvationAPIPA
⏱ 18–24 min
Intermediate
Start →
MODULE 19✓ LIVE

ICMP — Ping, Traceroute, and Error Messages

The control plane of IP — how ping works at the packet level, traceroute TTL trick, ICMP tunneling

ICMPPingTracerouteTTL exceededEcho requestEcho replyICMP tunnelingMTU discovery
⏱ 14–20 min
Intermediate
Start →
4
Section 4 — Transport Layer
MODULE 20✓ LIVE

TCP — The Protocol That Guarantees Delivery

3-way handshake byte by byte, sequence numbers, flow control, congestion control, FIN vs RST

TCPSYNACK3-way handshakeSequence numbersFlow controlCongestion controlRSTFIN
⏱ 22–30 min
Intermediate
Start →
MODULE 21✓ LIVE

UDP — When Speed Matters More Than Reliability

DNS, video, gaming, QUIC — why connectionless is the right choice more often than you think

UDPDatagramConnectionlessDNSVoIPGamingUDP floodAmplification attack
⏱ 14–20 min
Intermediate
Start →
MODULE 22✓ LIVE

Ports and Sockets — Where Applications Live

Well-known ports, ephemeral ports, socket pairs, how an OS routes packets to the right process

PortsSocketsWell-known portsEphemeral portsSocket pairnetstatssTCP states
⏱ 16–22 min
Intermediate
Start →
MODULE 23✓ LIVE

TLS — How Encryption Protects Every HTTPS Request

Certificate chain, handshake byte by byte, cipher suites, HSTS, certificate pinning, TLS 1.3 vs 1.2

TLSSSLCertificateCAHandshakeCipher suiteHSTSSNIPerfect forward secrecyTLS 1.3
⏱ 22–30 min
Intermediate
Start →
MODULE 24✓ LIVE

QUIC and HTTP/3 — The Future of Web Transport

How Google replaced TCP+TLS for web traffic — 0-RTT, stream multiplexing, connection migration

QUICHTTP/30-RTTMultiplexingHead-of-line blockingConnection migrationUDP-based
⏱ 14–20 min
Intermediate
Start →
5
Section 5 — Application Layer Protocols
MODULE 25✓ LIVE

DNS — How Domain Names Become IP Addresses

Recursive resolution step by step, all record types, zone transfers, cache poisoning, DNS over HTTPS

DNSA recordMXCNAMETXTSOANSRecursive resolverDNSSECCache poisoningDoH
⏱ 22–30 min
Intermediate
Start →
MODULE 26✓ LIVE

HTTP and HTTPS — The Protocol Powering the Web

Request-response lifecycle, all headers, methods, status codes, cookies, HTTP/2 multiplexing

HTTPHTTPSGETPOSTPUTDELETEStatus codesHeadersCookiesHTTP/2Keep-alive
⏱ 22–30 min
Intermediate
Start →
MODULE 27✓ LIVE

Email Protocols — SMTP, IMAP, POP3, SPF, DKIM, DMARC

How email actually travels from sender to inbox — and the three records that stop spoofing

SMTPIMAPPOP3SPFDKIMDMARCMX recordPhishing infrastructureEmail headers
⏱ 18–26 min
Intermediate
Start →
MODULE 28✓ LIVE

SSH — Secure Shell Complete Guide

How SSH key exchange works, agent forwarding, tunneling, ProxyJump — and every hardening step

SSHRSAEd25519Key exchangeAgent forwardingTunnelingProxyJumpsshd_configHardening
⏱ 20–28 min
Intermediate
Start →
MODULE 29✓ LIVE

FTP, SFTP, and Secure File Transfer

Active vs passive mode, why FTP is dangerous, SFTP vs FTPS vs SCP, real-world file transfer

FTPSFTPFTPSSCPActive modePassive modeCredentials in cleartextrsync
⏱ 14–20 min
Intermediate
Start →
MODULE 30✓ LIVE

DHCP Deep Dive — Address Assignment Under the Hood

DORA byte by byte, option 43, relay agents, rogue DHCP servers, starvation and spoofing attacks

DHCPDORADiscoverOfferRequestACKOption 53Relay agentRogue DHCPStarvation
⏱ 16–22 min
Intermediate
Start →
MODULE 31✓ LIVE

SNMP and Syslog — How Networks Are Monitored

MIB, OID, traps, community strings — and why SNMPv1 is a security disaster still running in 2026

SNMPSNMPv3MIBOIDTrapCommunity stringSyslogSeverity levelsLog aggregation
⏱ 14–20 min
Intermediate
Start →
MODULE 32✓ LIVE

NTP — Why Clock Synchronisation Is a Security Issue

Stratum levels, how NTP works, why wrong clocks break TLS certificates and Kerberos authentication

NTPStratumClock driftNTP amplificationAuthenticated NTPKerberos time window
⏱ 12–16 min
Intermediate
Start →
6
Section 6 — Network Security
MODULE 33✓ LIVE

Network Attacks — ARP Poisoning, MITM, Sniffing

Every Layer 2 and Layer 3 attack — how they work, what they look like in Wireshark, how to defend

ARP poisoningMITMMAC floodingVLAN hoppingSniffingPassive vs activeEttercapResponder
⏱ 22–30 min
Advanced
Start →
MODULE 34✓ LIVE

Firewalls, ACLs, and Stateful Inspection

Stateless vs stateful vs NGFW, ACL rule order, DMZ design, common bypass techniques

Stateless firewallStateful firewallNGFWACLDMZRule orderNAT firewallBypass
⏱ 20–28 min
Advanced
Start →
MODULE 35✓ LIVE

IDS and IPS — Detecting Attacks on the Wire

Signature vs anomaly detection, Snort/Suricata rules, inline vs passive, evasion techniques

IDSIPSSnortSuricataSignatureAnomalyInlinePassiveFalse positiveEvasion
⏱ 18–26 min
Advanced
Start →
MODULE 36COMING SOON

VPNs and Tunneling — IPSec, SSL, WireGuard

How VPNs encrypt and encapsulate traffic — IKEv2, OpenVPN, WireGuard compared byte by byte

VPNIPSecIKEv2OpenVPNWireGuardTunnel modeTransport modeSplit tunnelingGRE
⏱ 20–28 min
Advanced
Soon
MODULE 37COMING SOON

Wireless Security — WPA2/WPA3 Attacks

KRACK, PMKID attack, deauth frames, evil twin AP, rogue AP detection — complete wireless attack surface

WPA2WPA3KRACKPMKID4-way handshakeDeauthEvil twinaircrack-nghcxtools
⏱ 20–28 min
Advanced
Soon
MODULE 38COMING SOON

Zero Trust Networking — Never Trust, Always Verify

BeyondCorp, microsegmentation, identity-based perimeter, ZTNA vs VPN — the architecture replacing VPNs

Zero trustBeyondCorpMicrosegmentationZTNAIdentity perimeterSDPSASEmTLS
⏱ 16–22 min
Advanced
Soon
MODULE 39COMING SOON

DDoS — How It Works and How to Defend Against It

Volumetric, protocol, application layer — Cloudflare, AWS Shield, anycast — real attack breakdowns

DDoSVolumetricSYN floodHTTP floodAmplificationCloudflareBGP anycastRate limiting
⏱ 18–24 min
Advanced
Soon
7
Section 7 — Tools and Troubleshooting
MODULE 40COMING SOON

Network Troubleshooting Methodology

The OSI-layer-by-layer methodology that resolves 90% of issues — with every command you run at each step

Troubleshootingpingtraceroutenslookupnetstatssip routearp -aMethodology
⏱ 18–24 min
Advanced
Soon
MODULE 41COMING SOON

Wireshark — Packet Analysis Complete Guide

Capture filters, display filters, following streams, decrypting TLS, real-world pcap analysis

WiresharkCapture filterDisplay filterTCP streampcapDecrypting TLSProtocol dissector
⏱ 22–30 min
Advanced
Soon
MODULE 42COMING SOON

tcpdump — Command-Line Packet Capture

BPF filter syntax, writing pcaps, piping to Wireshark — the tool every Linux engineer needs

tcpdumpBPFCapture filterpcap-w flag-r flagExpressionsRemote capture
⏱ 16–22 min
Advanced
Soon
MODULE 43COMING SOON

Nmap — Network Scanning and Host Discovery

SYN scan, OS fingerprinting, NSE scripts, timing, evading firewalls — complete offensive and defensive use

NmapSYN scan-sV-ONSETimingFirewall evasionHost discoveryPort states
⏱ 20–28 min
Advanced
Soon
MODULE 44COMING SOON

Network Monitoring — NetFlow, SNMP Polling, Dashboards

How enterprise networks are observed at scale — NetFlow, SNMP polling, Grafana, alerting

NetFlowsFlowSNMP pollingGrafanaPrometheusAlertmanagerBandwidth monitoringNOC
⏱ 16–22 min
Advanced
Soon
Ready to go deeper?

After completing this course, the Cybersecurity track picks up exactly where you leave off — using these networking fundamentals to understand attacks, defences, and professional security work.

Start Cybersecurity Course →
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