Operating Systems and Networking Basics
The Operating Systems and Networking Basics domain tests OS functions, file systems, user accounts, basic IPv4 addressing and connectivity tools. Expect practical questions on IP configuration, DNS/DHCP and troubleshooting.
Core rules and concepts
- OS functions: process and memory management, file system, device drivers, user accounts and permissions, updates and security.
- File systems: NTFS and FAT32/exFAT on Windows; ext4 on Linux; FAT32 has a 4 GB single-file limit. Permissions should follow least privilege.
- IPv4 address = 32 bits, written as four octets. A /24 subnet mask 255.255.255.0 gives 256 addresses: 254 usable hosts, one network and one broadcast address.
- Private ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. APIPA 169.254.x.x means DHCP failed.
- DHCP assigns addresses; DNS resolves names to IPs; the default gateway routes traffic off-LAN. Diagnostic commands: ipconfig, ping, tracert, nslookup.
Worked example
A PC has 192.168.1.50/24 and gateway 192.168.1.1. The network address is 192.168.1.0, broadcast is 192.168.1.255, and usable hosts are 192.168.1.1–192.168.1.254. The PC can reach local hosts directly; traffic to 8.8.8.8 goes via the gateway. If ping to 192.168.1.1 fails but ping 127.0.0.1 works, check the cable, switch port and local IP settings.
Traps that cost marks
Confusing subnet mask with an IP address; counting the network and broadcast as usable; assuming DNS assigns IP addresses; ignoring APIPA; using public ranges internally without planning; forgetting that ping may be blocked by a firewall.