300-915 · Question #56
A network is being configured for an Ethernet-connected sensor. The sensor fails to send data to the configured destination. The IP address of the sensor can be pinged from a laptop on the same…
The correct answer is C. wrong default gateway on the sensor E. wrong subnet mask on the sensor. Options C and E are correct because the symptoms point to misconfiguration on the sensor itself, specifically its ability to communicate outside its local subnet. Why C (wrong default gateway on the sensor): When the sensor tries to send data to a destination on a different…
Question
A network is being configured for an Ethernet-connected sensor. The sensor fails to send data to the configured destination. The IP address of the sensor can be pinged from a laptop on the same subnet. When a different subnet is used, the sensor cannot be reached, but other clients on the same subnet are still accessible. What are two reasons for the connectivity problem? (Choose two.)
Options
- Awrong DNS server on the sensor
- Bwrong subnet mask on your laptop
- Cwrong default gateway on the sensor
- Dwrong default gateway on your laptop
- Ewrong subnet mask on the sensor
How the community answered
(21 responses)- A10% (2)
- B29% (6)
- C57% (12)
- D5% (1)
Explanation
Options C and E are correct because the symptoms point to misconfiguration on the sensor itself, specifically its ability to communicate outside its local subnet.
Why C (wrong default gateway on the sensor): When the sensor tries to send data to a destination on a different subnet, it must forward packets to its default gateway. If the gateway IP is wrong or missing, the sensor has no route off its local network - so it can still respond to local pings (same subnet, no gateway needed) but cannot reach anything beyond it.
Why E (wrong subnet mask on the sensor): A wrong subnet mask causes the sensor to miscalculate which addresses are "local" vs. "remote." For example, a mask that's too broad might make the sensor think a remote host is on the same subnet, so it ARPs directly instead of routing through the gateway - causing silent delivery failures.
Why the distractors are wrong: A (wrong DNS) would break name resolution but not IP-based communication. B (wrong subnet mask on the laptop) would affect the laptop's routing, not the sensor's ability to initiate connections. D (wrong default gateway on the laptop) would prevent the laptop from reaching the sensor from another subnet, but the problem states the sensor itself can't reach the destination, and other same-subnet clients work fine.
Memory tip: Think "the victim has the bug" - since the sensor alone fails to send outbound data while everything else works, the misconfiguration must live on the sensor. Gateway = routing out; subnet mask = knowing what's "out" in the first place.
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