Match List-I of firewalls with List-II of their usage. Select the correct…
2021
Match List-I of firewalls with List-II of their usage. Select the correct answer from the given options.
- A.
a-iv, b-ii, c-iii, d-i
- B.
a-ii, b-i, c-iv, d-iii
- C.
a-i, b-iv, c-ii, d-iii
- D.
a-iii, b-i, c-iv, d-ii
Attempted by 26 students.
Show answer & explanation
Correct answer: A
Concept
A firewall's category is defined by the OSI layer it operates at and the kind of state it keeps. Packet filters work at the network/transport layer on individual packets; stateful firewalls add a connection-state table; proxy (application-gateway) firewalls terminate a connection and relay a specific service; application-level firewalls parse the full application protocol. Each type therefore has a characteristic deployment context, and the match follows from which mechanism each context needs.
Application
Pairing each firewall in List-I with the usage in List-II that its mechanism is built for:
Firewall (List-I) | Mechanism | Usage (List-II) |
|---|---|---|
Stateful inspection firewall | Maintains a connection-state table, so it can admit return packets that belong to an already-tracked session | Inbound network traffic |
Packet filter firewalls | Simplest, rule-based per-packet check on IP/port; the lightweight filter bundled with the host | Operating systems |
Proxy server firewalls | Terminates the connection and relays one named service on the client's behalf | Mail servers |
Application level firewalls | Parses a full application-layer protocol to allow or block specific commands | Telnet |
Cross-check
Reading the pairs as a chain a-iv, b-ii, c-iii, d-i: stateful inspection guards inbound sessions, the OS ships a basic packet filter, a proxy fronts a service such as mail, and an application-level firewall inspects a protocol such as Telnet. Each distractor breaks at least one of these links (for example pairing a per-packet filter with Telnet, or a stateful firewall with mail), so a-iv, b-ii, c-iii, d-i is the only fully consistent mapping.