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GSEC · Question #325

What is the purpose of a TTL value?

The correct answer is A. It represents of hops that a packet can take before being discarded.. TTL (Time to Live) limits how many router hops a packet can traverse before being discarded, preventing packets from circulating indefinitely on a network.

Networking and Core Concepts

Question

What is the purpose of a TTL value?

Options

  • AIt represents of hops that a packet can take before being discarded.
  • BIt represents the time in minutes that a packet can live before being discarded.
  • CIt represents the value that the sequence number should be Incremented by during the next
  • DIt represents the number of gateways the packet has passed through and is Increased by 1 for

How the community answered

(35 responses)
  • A
    77% (27)
  • B
    14% (5)
  • C
    3% (1)
  • D
    6% (2)

Why each option

TTL (Time to Live) limits how many router hops a packet can traverse before being discarded, preventing packets from circulating indefinitely on a network.

AIt represents of hops that a packet can take before being discarded.Correct

TTL is an 8-bit field in the IP header that is decremented by 1 at each router hop; when the value reaches zero, the packet is discarded and an ICMP 'Time Exceeded' message is returned to the source. This hop-count mechanism prevents routing loops from consuming network resources indefinitely.

BIt represents the time in minutes that a packet can live before being discarded.

TTL is not measured in minutes or any time unit - it is strictly a hop counter decremented by each forwarding router, not a clock-based timer.

CIt represents the value that the sequence number should be Incremented by during the next

Sequence number incrementing is a TCP mechanism for reliable data ordering and has no relation to the TTL field in the IP header.

DIt represents the number of gateways the packet has passed through and is Increased by 1 for

TTL is decremented (not incremented) at each hop and represents the number of hops remaining, not the cumulative count of gateways already traversed.

Concept tested: IP TTL hop-count packet lifetime mechanism

Source: https://datatracker.ietf.org/doc/html/rfc791

Topics

#TTL#packet routing#IP protocol#hop count

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