Quick Revision

GK One-Line Question & Answer

15541+ short questions with short answers, covering every category and sub-category on the site — no long articles to scroll through. Good for a fast recap before an exam, or a few minutes of daily practice.

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Computer Fundamentals → Introduction to Computer 38

PMTUD (Path MTU Discovery) determines?
Maximum packet size that can traverse the entire path without fragmentation
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Which IPv4 header field prevents routing loops?
TTL (Time To Live)
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OSPFv3 vs OSPFv2: OSPFv3 is designed for?
IPv6
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IS-IS routing protocol runs on?
Directly on Data Link layer (Layer 2) — no IP dependency
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RIP v2 maximum hop count is?
15
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Which protocol provides gateway redundancy (failover)?
HSRP (Cisco) / VRRP (standard)
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VRRP master election is based on?
Highest priority value (default 100)
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GRE (Generic Routing Encapsulation) tunnel?
Encapsulates packets of one protocol inside another protocol
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IPsec transport mode vs tunnel mode: tunnel mode?
Encapsulates and encrypts the entire original IP packet
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Which multicast protocol manages group membership on local networks?
IGMP (IPv4) / MLD (IPv6)
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PIM (Protocol Independent Multicast) is used for?
Routing multicast traffic between routers
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Anycast routing delivers packets to?
Nearest node in a group
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Which network protocol provides loop-free path selection in Layer 2?
STP/RSTP
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MSTP (802.1s) improves on RSTP by?
Supporting multiple spanning tree instances per VLAN group
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Which HTTP method is idempotent but NOT safe?
PUT
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HTTP/2 improvements over HTTP/1.1 include?
Binary framing, header compression (HPACK), multiplexing, server push
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gRPC uses which protocol and format?
HTTP/2 + Protocol Buffers (binary)
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Which protocol enables real-time bidirectional streaming?
WebSocket
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Server-Sent Events (SSE) provides?
One-way server-to-client real-time updates over HTTP
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Long polling technique?
Keeps HTTP connection open until server has new data, then reconnects
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SPF (Sender Policy Framework) prevents?
Email spoofing by listing authorized mail servers for a domain
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DMARC builds on SPF and DKIM by?
Providing policy for handling authentication failures and reporting
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Which protocol assigns MAC address for a given IP in IPv4?
ARP
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RARP (Reverse ARP) does?
MAC to IP mapping (predecessor to BOOTP/DHCP)
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BOOTP precedes which modern protocol?
DHCP
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TFTP uses which transport protocol?
UDP (port 69)
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SFTP vs SCP: SFTP provides?
Full file management (list, delete, rename) over SSH
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Which protocol synchronizes time with microsecond precision?
PTP (Precision Time Protocol IEEE 1588)
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SNMP trap vs SNMP polling: trap is?
Device sends unsolicited notification to manager on event
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Which SNMP version provides strongest security?
SNMPv3
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Syslog protocol sends log messages to?
Central syslog server (UDP/TCP port 514 or 6514 TLS)
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NetFlow/IPFIX is used for?
Network traffic flow monitoring and analysis
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Which protocol provides link-level flow control using PAUSE frames?
Ethernet flow control (IEEE 802.3x)
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LLDP (Link Layer Discovery Protocol) allows?
Network devices to advertise identity and capabilities to neighbors
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CDP (Cisco Discovery Protocol) is?
Cisco proprietary neighbor discovery protocol
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Which protocol provides dynamic port security?
802.1X
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DHCP Snooping prevents?
Rogue DHCP servers by filtering DHCP messages on untrusted ports
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Dynamic ARP Inspection (DAI) prevents?
ARP spoofing/poisoning by validating ARP packets against DHCP Snooping binding table
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Computer Fundamentals → Internet Basics 2

IKE (Internet Key Exchange) in IPsec is used for?
Negotiating and establishing Security Associations (key exchange)
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Which DNS record type is used for email authentication (DKIM)?
TXT (with DKIM public key)
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