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Network Configuration & Internet Connections

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CompTIA A+ 220-1201 & 220-1202

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1 Introduction & Exam Overview

About the CompTIA A+ Certification Exam Domains & Study Strategy

2 Core 1 Domain 1: Mobile Devices (13%)

Laptop Hardware & Components Laptop Features & Display Types Mobile Device Connectivity & Accessories Mobile Operating System Features Mobile Device Synchronization & Data Transfer

3 Core 1 Domain 2: Networking (23%)

TCP/IP Fundamentals & the OSI Model Common Ports & Protocols Wireless Networking Standards Network Hardware & Devices Network Configuration & Internet Connections Network Types & Topologies

4 Core 1 Domain 3: Hardware (25%)

Cables & Connectors RAM Types & Storage Devices Motherboards, CPUs & Power Supplies Printers & Multifunction Devices Peripheral Devices & Expansion Cards Network Cable Tools & Testing

5 Core 1 Domain 4: Virtualization & Cloud Computing (11%)

Virtualization Concepts Cloud Computing Models & Services Client-Side Virtualization in Practice

6 Core 1 Domain 5: Hardware & Network Troubleshooting (28%)

CompTIA Troubleshooting Methodology Hardware Troubleshooting Network Troubleshooting Printer Troubleshooting Display & Mobile Device Troubleshooting

7 Core 2 Domain 1: Operating Systems (28%)

Windows Editions & Features Windows Administrative Tools & Utilities Windows Command Line & PowerShell macOS & Linux Basics Windows Networking & File Sharing Windows Installation & Upgrade Methods

8 Core 2 Domain 2: Security (28%)

Physical & Logical Security Measures Malware Types & Threat Mitigation Wireless & Network Security Encryption & Data Protection

9 Core 2 Domain 3: Software Troubleshooting (23%)

Windows OS Troubleshooting Mobile OS & Application Troubleshooting Browser & Application Troubleshooting

10 Core 2 Domain 4: Operational Procedures (21%)

Documentation & Change Management Backup & Recovery Methods Safety & Environmental Procedures Scripting & Remote Access Technologies Privacy, Licensing & Organizational Policies

Network Configuration & Internet Connections

Key Takeaways Explain This Topic AI

Static IPs are configured by hand for servers, printers, and infrastructure; dynamic IPs come from DHCP; a DHCP reservation gives a device a fixed address while still using DHCP.

NAT lets private hosts share a public IP; PAT (NAT overload) is the home-router default, distinguishing flows by port.

A VPN builds an encrypted tunnel; full tunnel sends all traffic through it while split tunnel sends only corporate traffic.

Connection types differ sharply in latency: GEO satellite is 500-700ms (poor for real-time), while fiber is ~1-5ms.

Know the ipconfig family for Windows: /all, /release, /renew, and /flushdns, plus ping, tracert, and nslookup.

Last updated: June 2026

  • Static vs. Dynamic Addressing
  • Dynamic (DHCP) - the default for clients

Assigned automatically; may change at lease renewal.

Best for laptops, desktops, and phones; no manual setup.

Static - manual and fixed

Use for devices that must always be reachable at the same address:

  • Servers (web, mail, file, print)
  • Network printers
  • Routers and switches
  • DNS and DHCP servers

A static host requires four values configured by hand: IP address, subnet mask, default gateway, and DNS server . Omitting the gateway is a classic exam fault - the host reaches its own subnet but nothing beyond it.

DHCP reservation - best of both

The DHCP server always hands a chosen device (matched by MAC address) the same IP. The device stays automatic but gets a predictable address - ideal for shared printers.

NAT (Network Address Translation)

  • Type Mapping Use case
  • Static NAT One private <-> one public A server that needs a permanent public address
  • Dynamic NAT Pool of public IPs shared as needed Orgs with several public addresses
  • PAT (Port Address Translation) Many private -> one public, by port Home/SOHO networks

PAT, also called NAT overload , is what your home router uses: every device shares one public IP, and the router keeps a translation table keyed by source port to route replies back to the right host.

VPN (Virtual Private Network)

A VPN wraps traffic in an encrypted tunnel across untrusted networks.

  • Mode Behavior Use case
  • Site-to-site Joins two whole networks Branch office to HQ
  • Remote access (client-to-site) One user dials into the corporate net Teleworkers
  • Split tunnel Only corporate traffic uses the tunnel Saves bandwidth
  • Full tunnel All traffic traverses the tunnel Maximum inspection/security

Protocols: IPSec (Layer 3 standard), SSL/TLS VPN (rides port 443 through browsers/firewalls), WireGuard (modern, lightweight), and OpenVPN (open-source, flexible).

Internet Connection Types

  • Connection Download Latency Where used
  • Cable (DOCSIS 3.1) 100 Mbps - 1 Gbps 15-30 ms Suburban/urban
  • DSL (VDSL2) 25-100 Mbps 20-40 ms Wide (phone lines)
  • Fiber (FTTH) 100 Mbps - 10 Gbps 1-5 ms Growing
  • Satellite (LEO/Starlink) 50-200 Mbps 20-40 ms Global
  • Satellite (GEO) 12-100 Mbps 500-700 ms Remote/legacy
  • Cellular 5G 100 Mbps - 1 Gbps 10-30 ms Urban/suburban
  • Fixed wireless 25-1000 Mbps 10-30 ms Rural/suburban

Exam tip: GEO satellite sits ~35,786 km up, so round-trip latency is 500-700 ms - unusable for VoIP, video calls, and gaming. LEO satellite (Starlink) flies much lower and slashes latency.

Proxy Servers

  • Type Path Benefit
  • Forward proxy Client -> proxy -> internet Content filtering, hide client identity
  • Reverse proxy Internet -> proxy -> server Load balancing, caching, TLS offload
  • Transparent proxy Intercepts without client config Org-wide filtering
  • Command-Line Diagnostics
  • Command OS Purpose
  • ipconfig /all Windows Full config: MAC, DHCP server, DNS, lease
  • ipconfig /release Windows Drop the current DHCP lease
  • ipconfig /renew Windows Request a fresh DHCP lease
  • ipconfig /flushdns Windows Clear the DNS resolver cache
  • ip addr Linux Show interface addressing
  • ping All Test reachability and round-trip time
  • tracert / traceroute Win / *nix Show each hop to a destination
  • nslookup All Query DNS records directly
  • netstat All List active connections and listening ports

A typical workflow: ipconfig /all to confirm a lease, ping the gateway then a public IP, and nslookup to isolate DNS. If a renamed site loads slowly or wrongly, ipconfig /flushdns clears stale cached records.

Static vs. Reservation: Choosing the Right Tool

Candidates often confuse a static IP with a DHCP reservation , and the exam exploits that. A static IP is typed into the device itself and lives nowhere else, so if the subnet is renumbered you must touch every static device by hand. A reservation lives on the DHCP server: the device still boots, sends a DHCP Discover, and receives the same address every time because the server matched its MAC.

The practical rule is to use a reservation whenever you want a predictable address but central control - network printers and IP cameras are textbook cases - and reserve true static configuration for the infrastructure that must work even if DHCP is down, such as the DHCP server itself, the default gateway, and DNS servers. A device with a reservation but a DHCP outage will eventually fall to APIPA, whereas a statically configured device keeps its address regardless.

VPN Tunnel Modes in Practice

The difference between full tunnel and split tunnel is a common scenario question. In full tunnel, a remote worker's entire traffic stream - including their personal web browsing - travels encrypted to the corporate gateway and out from there, so security teams can inspect and filter everything but the company link carries all that load. In split tunnel, only traffic destined for corporate subnets enters the tunnel while ordinary internet traffic goes out the user's local connection, which conserves bandwidth and speeds streaming but reduces the organization's visibility.

Choosing between them is a security-versus-performance decision, and the exam expects you to map the requirement ("inspect all employee traffic" versus "reduce VPN bandwidth") to the correct mode.

A Connection-Type Scenario

A rural clinic needs reliable video conferencing and asks which internet service to buy. Fiber is unavailable, and the candidate must reason from latency. GEO satellite is ruled out immediately - its 500-700 ms delay makes interactive video painful. LEO satellite such as Starlink, fixed wireless , or cellular 5G all deliver latency in the 10-40 ms range that video calls tolerate, so any of those is acceptable where coverage exists.

The reasoning - that real-time applications are dominated by latency, not raw download speed - is exactly the analysis the exam wants, and it explains why a fast-but-laggy GEO link feels worse on calls than a slower low-latency one.