Provide the best matching between the entries in the two columns given in the table below: Column I: Column II: I. Proxy Server a. Firewall II. Kanna, DC++ b. Caching III. Slip c. Nat IV. DNS d. PPP A. I-a, II-d, III-c, IV-b B. I-b, II-c, III-d, IV-a C. I-a, II-b, III-c, IV-d D. I-b, II-c, III-a, IV-d

GATE 2008 · Computer Networks · Application Layer Protocols · medium

Answer: B. I-b, II-c, III-d, IV-a

1. Match Proxy Server and SLIP: Proxy Server is best known for Caching (b) - it caches web content to serve multiple users faster. SLIP (Serial Line IP) is the predecessor of PPP (d) - both are point-to-point serial protocols, with PPP being the improved version. So I->b and III->d.
2. Match Kanna/DC++ and DNS: Kanna and DC++ are peer-to-peer file sharing programs. P2P applications frequently deal with NAT (c) - Network Address Translation - because users are behind home routers with private IPs. So II->c. That leaves DNS matched with Firewall (a). DNS can function as a firewall by blocking resolution of malicious domains (DNS RPZ - Response Policy Zones). So IV->a. Final matching: I-b, II-c, III-d, IV-a = Option B.