Free Network+ Cheat Sheet 2026: Azure Fundamentals Quick Reference

Networking Concepts

23%of exam

OSI Layers Ports Addressing MediaCloud Models

Network Implementation

20%of exam

RoutingSwitchingWireless Services Implementation Picker

Network Operations

19%of exam

MonitoringDocumentationChange ControlResilienceOperations Picker

Network Security

14%of exam

Security Controls Attack CuesAAASegmentationIDS vs IPS

Network Troubleshooting

24%of exam

MethodologyTroubleshooting Tools Symptom CuesWireless TroubleshootingTool Picker

Quick Facts

Exam: N10-009
Credential: Network+
Time: 90 min
Questions: Max 90
Format: MCQ + PBQ
Pass: 720/900
Launch: Jun 20 2024
Experience: A+ + 9-12 mo

OSI Order

Please Do Not Throw Sausage Pizza Away

PhysicalData LinkNetworkTransportSessionPresentationApplication

TCP vs UDP

TCP

Connection-oriented
Reliable delivery
Handshake

UDP

Connectionless
Low overhead
No delivery guarantee

Reliability vs speed

Protocol Picker

Secure shell→SSH(TCP 22)
Secure file transfer→SFTP(TCP 22)
Plain file transfer→FTP(20/21)
Name resolution→DNS(53)
Address leasing→DHCP(67/68)
Encrypted web→HTTPS(443)
Remote desktop→RDP(3389)
Device polling→SNMP(161)

OSI Layers

L1 Physical: Bits and media
L2 Data Link: Frames and MACs
L3 Network: IP routing
L4 Transport: TCP/UDP ports
L5 Session: Dialog control
L6 Presentation: Format/encryption
L7 Application: User services

Private IPv4

Private ranges: ten, seventeen, one-ninety-two

10/8172.16/12192.168/16

Ports

FTP 20/21: Plain file transfer
SFTP 22: SSH file transfer
SSH 22: Secure shell
Telnet 23: Plain remote shell
SMTP 25: Mail send
DNS 53: Name resolution
DHCP 67/68: Address leasing
HTTP 80: Plain web
HTTPS 443: Encrypted web
SNMP 161: Device monitoring
LDAP 389: Directory queries
LDAPS 636: Secure directory
RDP 3389: Remote desktop
NTP 123: Time sync
SIP 5060: Voice signaling
TFTP 69: Plain UDP transfer

Addressing

10.0.0.0/8: Private IPv4
172.16.0.0/12: Private IPv4
192.168.0.0/16: Private IPv4
169.254.0.0/16: APIPA
127.0.0.1: Loopback
FE80::/10: IPv6 link-local
2000::/3: IPv6 global
FF00::/8: IPv6 multicast
::1: IPv6 loopback
/30: Two usable hosts
/27: Thirty usable hosts
VLSM: Variable subnet sizing

Media

Cat 5e: Gigabit copper
Cat 6: Higher-speed copper
Cat 6A: 10G copper
SMF: Long-distance fiber
MMF: Shorter fiber
DAC: Short data-center link
Coax: Broadband RF media
RJ45: Twisted-pair Ethernet
LC: Common fiber connector
MPO: High-density fiber

Wireless Bands

2.4 reaches; 5 speeds; 6 clears

2.4 = range5 = capacity6 = clean

Switch vs Router

Switch

Layer 2
MAC forwarding
Same VLAN

Router

Layer 3
IP forwarding
Between networks

Frames vs packets

Implementation Picker

Separate broadcasts→VLAN(Layer 2)
Route VLANs→SVI(Layer 3)
Avoid switch loops→STP(Blocks path)
Bundle links→LACP(Port channel)
Share public IP→PAT(Overload)
Gateway failover→FHRP(VIP)
Mix WAN links→SD-WAN(Path control)
Private carrier WAN→MPLS(Provider core)

Routing + Switching

Static route: Manual path
OSPF: Link-state IGP
EIGRP: Advanced distance vector
BGP: Path-vector EGP
NAT: Address translation
PAT: Port overload
FHRP: Gateway redundancy
VLAN: Broadcast segmentation
Trunk: Tagged VLAN link
Access port: Single VLAN
STP: Loop prevention
LACP: Link aggregation

VLAN vs Subnet

VLAN

Layer 2 segment
Broadcast boundary
Switch config

Subnet

Layer 3 range
IP boundary
Router config

Segmentation layers differ

Wireless

802.11n: Wi-Fi 4
802.11ac: Wi-Fi 5
802.11ax: Wi-Fi 6/6E
2.4 GHz: Range; interference
5 GHz: More channels
6 GHz: Clean spectrum
SSID: Network name
WPA3: Modern Wi-Fi security
Captive portal: Guest onboarding
Site survey: RF planning

DNS vs DHCP

DNS

Names to addresses
Records
Resolver clues

DHCP

Leases addresses
Options
Scope clues

Names vs leases

Services

A: Name to IPv4
AAAA: Name to IPv6
CNAME: Alias record
MX: Mail exchanger
TXT: Text metadata
SRV: Service location
DHCP scope: Address pool
Reservation: Fixed DHCP lease
Relay: DHCP across subnets
NTS: Secure time sync

Operations Picker

Track devices→Inventory(Ownership)
Track addresses→IPAM(Subnets)
Know normal→Baseline(Compare)
Collect events→Syslog(Logs)
View conversations→NetFlow(Traffic)
Inspect packets→Capture(Evidence)
Limit outage→RTO(Time)
Limit data loss→RPO(Data)

Monitoring

SNMP: Polls and traps
NetFlow: Traffic conversations
Syslog: Central event logs
SIEM: Security log correlation
Packet capture: Actual traffic evidence
Port mirror: Copy switch traffic
Baseline: Known normal
API: Automation interface
IPAM: Address management
Runbook: Repeatable procedure

Resilience + Docs

RPO: Acceptable data loss
RTO: Acceptable downtime
MTTR: Repair time
MTBF: Failure interval
Hot site: Ready recovery site
Warm site: Partially ready site
Cold site: Space and utilities
SLA: Service commitment
EOL: Lifecycle ending
Config backup: Restore device state

MFA Factors

Know, have, are: MFA needs variety

PasswordTokenBiometric

IDS vs IPS

IDS

Detects
Alerts
Out-of-band

IPS

Blocks
Inline
Drops traffic

Alert vs block

Security Controls

ACL: Traffic allow/deny
Firewall: Policy enforcement
NGFW: App-aware firewall
IDS: Detect and alert
IPS: Inline blocking
NAC: Access posture checks
802.1X: Port authentication
RADIUS: AAA for access
TACACS+: Device admin AAA
MFA: Multiple factor types
PKI: Certificate trust
Zero Trust: Verify every access

Stateful vs Stateless

Stateful

Tracks sessions
Return traffic aware
Context checks

Stateless

Packet rules
No session memory
Fast filtering

Context vs rules

Attack Cues

DDoS: Availability flood
ARP spoofing: False MAC mapping
DNS poisoning: Bad name answers
VLAN hopping: Escapes segmentation
MAC flooding: Overflows CAM table
Evil twin: Rogue Wi-Fi AP
On-path: Intercepts traffic
Phishing: Deceptive messages
Tailgating: Unauthorized following
Honeypot: Decoy system

RADIUS vs TACACS+

RADIUS

Access AAA
UDP common
Wireless/VPN

TACACS+

Admin AAA
TCP
Command authorization

Access vs admin

Troubleshooting Flow

Identify, theorize, test, plan, fix, verify, document

IdentifyTheoryTestPlanImplementVerifyDocument

Latency vs Jitter

Latency

Delay
Round-trip time
Slow response

Jitter

Delay variation
Voice distortion
Video stutter

Delay vs variation

Tool Picker

No link light→Cable tester(Layer 1)
Fiber distance fault→OTDR(Optical)
Names fail→nslookup(DNS)
Path stops→traceroute(Hops)
Ports unknown→netstat(Sockets)
Wi-Fi noise→Wi-Fi analyzer(RF)
Packet proof→Wireshark(Frames)
Route choice→Route table(Prefix)

Troubleshooting Tools

ping: ICMP reachability
traceroute: Path hops
nslookup: DNS queries
dig: Detailed DNS
ipconfig: Windows IP config
ifconfig: Unix interface config
ip: Linux networking
arp: IP-to-MAC cache
netstat: Connections and ports
ss: Socket statistics
Wireshark: Packet analysis
OTDR: Fiber fault distance

Symptom Cues

No link: Physical first
APIPA: DHCP failed
Names fail: Check DNS
Gateway works: Local path ok
Off-net fails: Gateway/routing issue
CRC errors: Cable/duplex issue
Runts: Undersized frames
Giants: Oversized frames
High jitter: Voice/video impact
Packet loss: Drops/retransmissions
Weak RSSI: Poor signal
Low SNR: Noisy RF

Common Traps

Ping Passing

ICMP works ≠ Service may fail

DNS Failure

Names fail ≠ IP may work

APIPA Cause

DHCP failed ≠ Cable not proven

Route Choice

Most specific wins ≠ Default route last

SSID Hiding

Name still visible ≠ Not real security

Trunk Ports

Tags many VLANs ≠ Access uses one

Process Order

Test theory first ≠ Then implement plan

Last Minute

1.Weights: 23/20/19/14/24
2.Troubleshooting is largest domain
3.Longest prefix wins routes
4.DNS names; DHCP leases
5.APIPA means DHCP failed
6.VLAN separates broadcasts
7.Trunk tags multiple VLANs
8.STP blocks Layer 2 loops
9.IDS alerts; IPS blocks
10.Document after verifying fix
11.PBQs: read task first
12.Secure management beats Telnet

CompTIA Network+

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