FPSC- Programmer (BS-17) - PMD High Yield - 2026 — Test 6

Correct Answer: A. Browser and OS cache or hosts file, then the recursive resolver, then the root, TLD, and authoritative servers
Explanation: The resolver queries the root servers, then the TLD servers (such as .pk or .com), and finally the domain's authoritative server. ALSO KNOW (related points): • Which DNS record specifies the mail servers for a domain? → MX • Which DNS record type is used for reverse lookups (from an IP address to a name)? → PTR

Correct Answer: A. 24 collision domains and 1 broadcast domain
Explanation: Each switch port is its own collision domain. Broadcasts still reach every port. ALSO KNOW (related points): • What does a hub do with an incoming frame? → It repeats the frame out of every other port, and all its ports share one collision domain • Which device separates broadcast domains by default? → Router

Correct Answer: B. A router or a Layer 3 switch (inter-VLAN routing)
Explanation: VLANs are separate broadcast domains, so traffic between them must be routed. ALSO KNOW (related points): • At which layer does a repeater operate, and what does it do? → Layer 1; it regenerates and amplifies the signal • What is the role of a modem? → It converts digital data to and from an analog or line signal (modulation and demodulation) • At which OSI layer does a bridge operate? → Layer 2 (Data Link)

Correct Answer: B. An IDS detects and alerts; an IPS sits inline and can block traffic
Explanation: An IPS sits in the traffic path, so it can drop malicious packets. ALSO KNOW (related points): • What does a stateful firewall do that a simple packet filter does not? → It tracks connection state and allows return traffic that belongs to an established session • A proxy server between users and the internet can do which of the following? → Cache content, filter requests, and hide the client's IP address from destination servers • Which device connects networks that use different protocols and translates between them? → Gateway

Correct Answer: D. 15
Explanation: n(n - 1)/2 = 6 × 5 / 2 = 15. ALSO KNOW (related points): • Which fiber type is used for longer distances? → Single-mode fiber • Bluetooth typically forms which type of network? → PAN (Personal Area Network) • What happens if a bus-topology coaxial cable has no terminator at one end? → Signal reflections cause collisions and network failure

Correct Answer: D. 100 meters
Explanation: 185 m and 500 m are the limits for the old 10Base2 and 10Base5 coaxial standards. ALSO KNOW (related points): • In a star topology, what happens if the central switch fails? → The whole network segment goes down • Why are the wire pairs in twisted-pair cable twisted? → To reduce electromagnetic interference and crosstalk

Correct Answer: C. Ethernet uses CSMA/CD; Wi-Fi uses CSMA/CA
Explanation: Wireless stations cannot detect collisions while transmitting, so they try to avoid them instead. Full-duplex switched Ethernet no longer needs CSMA/CD. ALSO KNOW (related points): • What is the standard Ethernet MTU? → 1500 bytes • Which Wi-Fi security protocol is the most current and secure? → WPA3 • Which standard is marketed as Wi-Fi 6? → 802.11ax • How does the 2.4 GHz Wi-Fi band compare with the 5 GHz band? → 2.4 GHz has longer range and better wall penetration but lower speeds and more interference • Which topology uses a token passed between nodes to control access to the medium? → Ring (Token Ring)

Correct Answer: D. It is created with the sender's private key and verified with the sender's public key
Explanation: Encryption for confidentiality uses the receiver's public key. A signature does the reverse, using the sender's private key. ALSO KNOW (related points): • How does TLS use cryptography? → Asymmetric cryptography for authentication and key exchange, then symmetric encryption for the bulk data • Which statement about cryptographic hashing (for example, SHA-256) is correct? → It is one-way and cannot be 'decrypted' back to the input • What does a VPN primarily provide? → An encrypted tunnel over an untrusted network • An attacker floods a weather data server from thousands of compromised machines. What is this attack called? → DDoS (Distributed Denial of Service) • Which statement about the World Wide Web and the Internet is correct? → The Web is one service (HTTP and hypertext) that runs on top of the Internet • An email that pretends to be from the HR department asks staff to 'verify' their passwords on a link. What is this attack called? → Phishing

Correct Answer: B. #top (the fragment)
Explanation: The browser handles the fragment client-side, for example by scrolling to that anchor. ALSO KNOW (related points): • Which Regional Internet Registry (RIR) allocates IP addresses for Pakistan? → APNIC • What switching method does the Internet use? → Packet switching • Where are HTTP cookies stored? → On the client (in the browser), which sends them back to the server with matching requests • A ping returns 'Destination host unreachable' from your own gateway, rather than 'Request timed out'. What does this most likely indicate? → A router (or your host) has no route to the destination, or ARP for the target failed

Correct Answer: A. 8 seconds
Explanation: Megabytes and megabits differ by a factor of 8: 100 MB = 800 Mb, and 800 Mb / 100 Mbps = 8 s. ALSO KNOW (related points): • What distinguishes bandwidth from latency? → Bandwidth is the data capacity per second; latency is the delay before data arrives • What does a CDN (Content Delivery Network) do? → It serves cached copies of content from servers geographically close to users • Which organization coordinates the Internet's domain name system and top-level domains globally? → ICANN