CompTIA A+ Core 1 (220-1101) Study Guide

Key concepts, port numbers, and specs you must know for the Core 1 exam.

1. Networking (27% of Core 1)

Networking is the largest domain. Know these cold:

Must-memorize ports: HTTP 80, HTTPS 443, FTP 20/21, SSH 22, Telnet 23, SMTP 25, DNS 53, DHCP 67/68, POP3 110, IMAP 143, RDP 3389, SMB 445

Cable Type	Speed	Max Distance
Cat 5e	1 Gbps	100m
Cat 6	1 Gbps (10 Gbps short range)	100m (55m at 10G)
Cat 6a	10 Gbps	100m
Fiber (Single-mode)	Up to 100 Gbps	40km+
Fiber (Multi-mode)	Up to 100 Gbps	550m

Wireless standards: 802.11a (5GHz, 54Mbps), 802.11b (2.4GHz, 11Mbps), 802.11g (2.4GHz, 54Mbps), 802.11n (2.4/5GHz, 600Mbps), 802.11ac/Wi-Fi 5 (5GHz, 3.5Gbps), 802.11ax/Wi-Fi 6 (2.4/5/6GHz, 9.6Gbps)

IPv4 private ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. APIPA = 169.254.x.x (no DHCP server found).

2. Hardware (25% of Core 1)

RAM types: DDR4 (most current), DDR5 (newest), SODIMM (laptops). ECC RAM corrects errors — used in servers.

Storage interfaces: SATA (6Gbps max), NVMe/M.2 PCIe (up to 7GB/s), SAS (enterprise HDDs). NVMe is dramatically faster than SATA SSD.

PCIe slots: x1, x4, x8, x16 (GPU). PCIe 4.0 doubles bandwidth of PCIe 3.0 per lane.

Connector	Use
24-pin ATX	Motherboard main power
8-pin EPS	CPU power
6+2 pin PCIe	Discrete GPU power
SATA power (15-pin)	Storage drives
Molex 4-pin	Legacy fans/optical drives

3. Mobile Devices (11% of Core 1)

Laptop display types: IPS (best color/viewing angle), TN (fastest refresh, gaming), OLED (deepest blacks, used in high-end laptops/phones).

Common laptop ports: USB-A, USB-C, Thunderbolt 3/4 (same connector as USB-C), HDMI, DisplayPort, SD card, 3.5mm audio, RJ-45 (on some models)

Mobile device management: MDM solutions push profiles, enforce encryption, enable remote wipe. BYOD policies balance personal use with corporate security.

4. Virtualization & Cloud (11% of Core 1)

Cloud models: IaaS (infrastructure — VMs, storage), PaaS (platform — databases, dev tools), SaaS (software — Office 365, Salesforce)

Cloud deployment: Public (AWS, Azure, GCP), Private (on-premises), Hybrid (both), Community (shared industry infrastructure)

Hypervisors: Type 1 (bare metal — VMware ESXi, Hyper-V) runs directly on hardware. Type 2 (hosted — VirtualBox, VMware Workstation) runs on top of an OS.

Container vs VM: Containers share the host OS kernel (lightweight, fast). VMs emulate full hardware (stronger isolation, heavier). Docker = most common container platform.

5. Hardware & Network Troubleshooting (26% of Core 1)

The exam loves troubleshooting scenarios. Follow a systematic process:

CompTIA troubleshooting steps: (1) Identify the problem, (2) Research knowledge base, (3) Establish a theory, (4) Test the theory, (5) Establish an action plan, (6) Implement the solution, (7) Verify full functionality, (8) Document findings

POST beep codes: 1 beep = successful POST. Multiple beeps indicate hardware failures (varies by BIOS manufacturer — AMI vs Award have different codes).

Common network fixes: ipconfig /release + /renew (refresh DHCP), ipconfig /flushdns (clear DNS cache), ping 127.0.0.1 (loopback test), tracert (path to destination), nslookup (DNS query).