NetworkingA+

Network Configuration for CompTIA A+ 220-1101

Network configuration is a daily task for A+ technicians — configuring IP addresses, DNS settings, and proxy settings on Windows, macOS, and mobile devices. CompTIA A+ 220-1101 tests how to configure both automatic (DHCP) and manual (static) IP settings, verify connectivity, and configure shared network resources. These skills are used on every support call involving network access.

7 min

2 sections · 7 exam key points

1 practice questions

IP Address Configuration on Windows

Accessing network settings: Control Panel → Network and Sharing Center → Change adapter settings → right-click adapter → Properties → Internet Protocol Version 4 (TCP/IPv4) → Properties. Or: Settings → Network & Internet → Ethernet/Wi-Fi → Change adapter options. IPv6: same path, use Internet Protocol Version 6 (TCP/IPv6).

DHCP vs static IP: Obtain an IP address automatically = DHCP (recommended for most devices). Use the following IP address = static configuration. Static IP requires: IP address, Subnet mask, Default gateway, Preferred DNS server, Alternate DNS server. Static IPs: use for servers, printers, network devices where a consistent address is required. Dynamic IPs: use for workstations and mobile devices.

DHCP reservation: configure on the DHCP server (router for SOHO) to always assign the same IP to a specific MAC address — provides the benefit of static addressing with the convenience of DHCP management. Preferred over static configuration on the device because all IP management happens in one place.

Verify configuration: 'ipconfig' (Windows) — displays IP address, subnet mask, default gateway for all adapters. 'ipconfig /all' — displays detailed info including MAC address, DHCP server, DNS servers, lease obtained/expires. 'ifconfig' (Linux/macOS legacy) or 'ip addr' (Linux modern). Check IPv4 and IPv6 separately.

DNS and Proxy Configuration

DNS server configuration: within TCP/IP properties, set preferred and alternate DNS servers. Common alternatives to ISP-provided DNS: Google (8.8.8.8 / 8.8.4.4), Cloudflare (1.1.1.1 / 1.0.0.1), OpenDNS (208.67.222.222 / 208.67.220.220). DNS affects name resolution speed and may enable content filtering (OpenDNS blocks malware domains by default). When troubleshooting: test with a known-good DNS server like 8.8.8.8 to isolate DNS issues from ISP DNS issues.

Proxy settings: a proxy server acts as an intermediary for web requests — the client sends requests to the proxy, which fetches content on behalf of the client. Enterprise environments use proxies for: content filtering, caching, logging, security inspection. Configure in Internet Explorer/Edge settings or system-wide: Settings → Network & Internet → Proxy. Common issue: proxy configured for work network, causes failure on home network — disable proxy when off-network or configure 'bypass proxy for local addresses'.

Alternative IP configuration (Windows): configured in IPv4 properties under 'Alternate Configuration' tab. If DHCP fails, Windows uses this static address instead of APIPA. Useful for: users who work between a DHCP network (home) and a static network (some office environments without DHCP) — they get automatic IP when DHCP is available but fall back to a known static address.

Key exam facts — A+

'ipconfig': shows current IP; '/all': shows MAC, DHCP server, DNS, lease info
Static IP requires: address, subnet mask, default gateway, DNS server(s)
DHCP reservation: same IP always to a specific MAC — configured on DHCP server, not device
Proxy server: enterprise intermediary for web requests — disable when off-network if auto-configured
Alternate IP configuration: fallback static IP when DHCP unavailable — prevents APIPA
Common DNS alternatives: Google 8.8.8.8, Cloudflare 1.1.1.1
IPv4 and IPv6 configured separately in network adapter properties

Common exam traps

Changing DNS settings requires changing the IP address

DNS server settings are independent of the IP address. You can use DHCP for the IP address but manually specify custom DNS servers (e.g., override ISP DNS with Google 8.8.8.8). Simply uncheck 'Obtain DNS server address automatically' while leaving 'Obtain an IP address automatically' checked — no static IP required

Practice questions — Network Configuration

These questions are representative of what you will see on A+ exams. The correct answer and explanation are shown immediately below each question.

Q1.A Windows user reports that websites are loading slowly and some sites don't load at all, but pinging 8.8.8.8 by IP works. The ISP has confirmed the internet connection is fine. What is the most efficient first step?

A.Replace the network cable

B.Change the DNS server in TCP/IP settings to 8.8.8.8 and test again

C.Reinstall Windows

D.Replace the network adapter

Explanation: Pinging by IP works means the network connection is good. DNS is the only remaining variable — the ISP's DNS server may be slow or partially failing. Changing the DNS server to 8.8.8.8 (Google's public DNS) immediately tests this hypothesis. If websites load normally after the change, the ISP's DNS was the problem. This is one of the fastest and most impactful first steps for slow/partial DNS issues. Reinstalling Windows or replacing hardware is never the first step for a DNS symptom.

Frequently asked questions — Network Configuration

What is the difference between 'ipconfig' and 'ipconfig /all'?

'ipconfig' (no flags) displays a summary: the IP address, subnet mask, and default gateway for each network adapter. 'ipconfig /all' displays the full details: MAC address (physical address), DHCP enabled/disabled, DHCP server IP, DNS server IPs, lease obtained date, lease expires date, and WINS server if configured. For troubleshooting, always use 'ipconfig /all' — it gives you all the information needed to diagnose IP configuration problems in one command.

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