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ITCA: ITCA: Foundational IT Concepts and Troubleshooting

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ITCA: Foundational IT Concepts and Troubleshooting

The ITCA exam tests entry-level IT literacy across computing, networking, security, data, and software. It rewards precise definitions and ordered troubleshooting, not product trivia.

Core rules and concepts

  • Computing: CPU executes instructions; RAM is volatile working memory; storage is persistent. The OS schedules processes and enforces permissions. Virtual machines run a full OS; containers share the host kernel.
  • Networking: MAC addresses are link-local; IP addresses are routable. Private IPv4 ranges: 10/8, 172.16/12, 192.168/16. DNS resolves names, DHCP leases addresses, TCP is reliable and ordered, UDP is low-latency. Ports: 22 SSH, 53 DNS, 80 HTTP, 443 HTTPS.
  • Security: CIA triad = confidentiality, integrity, availability. Authentication proves identity; authorization grants access. Use least privilege, MFA, and encryption in transit and at rest. Symmetric encryption uses one shared key; asymmetric uses a public/private key pair for exchange and signatures.
  • Data: A primary key is unique and non-null; a foreign key enforces referential integrity. SQL uses WHERE to filter and JOIN to combine tables. A 3-2-1 backup means three copies, two media types, one off-site.
  • Software: SDLC phases are requirements, design, implementation, testing, deployment, maintenance. Agile iterates; waterfall sequences. Version control tracks changes; APIs define contracts; tests range from unit to acceptance.

Worked example

A user cannot reach https://shop.example.com, but other sites load. Reason in layers. Other sites working suggests local DNS and internet path work; run nslookup. If the name resolves, test TCP 443: refusal points to a local firewall or stopped service; timeout suggests routing or filtering. A certificate warning means expired cert or name mismatch. If the page loads but login fails, move to application authorization.

Traps that cost marks

  • Confusing authentication with authorization.
  • Calling RAM storage; it is volatile memory.
  • Believing HTTPS encrypts server data at rest; it protects data in transit.
  • Allowing duplicate or null primary keys.
  • Rebooting before isolating the failing layer.