Ports, Protocols, Devices & Troubleshooting
Fast-reference Network+ notes for core networking concepts. Review the ideas, then reinforce them with original CertNivo practice questions.
Save / Print as PDFPractice Network+Common Ports
Secure remote administration.
Name resolution.
Automatic IPv4 configuration.
Unencrypted web traffic.
Encrypted web traffic.
Windows remote desktop.
Network Devices
Switch: forwards frames within a LAN, typically using MAC addresses. Router: forwards packets between IP networks. Firewall: permits or blocks traffic according to policy. Wireless access point: connects wireless clients to the network. Load balancer: distributes requests across resources.
Addressing Essentials
IPv4 private ranges: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. APIPA: 169.254.0.0/16 often indicates a client could not obtain normal DHCP configuration. A default gateway is used to reach destinations outside the local subnet.
Troubleshooting Clues
Investigate DNS.
Investigate DHCP/connectivity.
Check gateway/routing.
Check cable, port, transceiver and errors.
Practical Workflow
Identify → Establish theory → Test theory → Plan → Implement → Verify → Document
Exam habit: separate symptoms by layer. Ask whether the evidence points first to physical connectivity, addressing, name resolution, routing, security policy, or application service.
Mini Check
A workstation has address 169.254.44.12 and cannot reach normal network resources. Which service should you investigate first?
Answer: DHCP. The automatic private address is a strong clue that normal DHCP configuration was not obtained.
Practice what you reviewed
Complete a short Network+ practice session and review why every option is right or wrong.
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