Why does L4TM require T1 to be in promiscuous mode?

The correct answer is B. To process traffic that is not intended for its MAC address. B is correct because L4TM functions as a passive traffic monitor that must inspect all packets traversing a network segment - including those addressed to other hosts. Without promiscuous mode, a NIC silently discards frames whose destination MAC doesn't match its own, making…

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Question

Options

ATo transmit TCP reset packets
BTo process traffic that is not intended for its MAC address
CTo receive Ethernet broadcasts
DTo bind with other promiscuous mode ports

How the community answered

(40 responses)

A
5% (2)
B
73% (29)
C
10% (4)
D
13% (5)

Explanation

B is correct because L4TM functions as a passive traffic monitor that must inspect all packets traversing a network segment - including those addressed to other hosts. Without promiscuous mode, a NIC silently discards frames whose destination MAC doesn't match its own, making most traffic invisible to the monitor.

A is wrong because transmitting TCP resets is an active response function, unrelated to how the interface receives packets. Promiscuous mode governs reception behavior, not transmission.

C is wrong because Ethernet broadcasts (destination MAC FF:FF:FF:FF:FF:FF) are delivered to all interfaces by default - promiscuous mode isn't needed to receive them.

D is wrong because promiscuous mode is a local interface setting; there is no protocol mechanism for ports to "bind" with each other based on this flag.

Memory tip: Think "promiscuous = nosy." A promiscuous NIC listens to conversations not meant for it - exactly what a traffic monitor needs to do its job.

Topics

#Layer 4 Traffic Management#Promiscuous Mode#Interface Configuration#Traffic Interception

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