A user returns from a trip and discovers a computer that is connected to the...

D. Crimper:

A crimper is used to terminate an RJ45 cable properly by attaching the connector to the twisted-pair wires.

If the termination is not done correctly, the connection will be intermittent or fail entirely.

Incorrect Options:

A. Toner probe: Used to locate cables or trace their path, not for terminating RJ45 connectors.

B. Cable tester: Useful for testing connectivity but does not fix termination issues.

C. Punchdown: Used to connect wires to a patch panel or keystone jack, not for RJ45 connectors.

Key Takeaway: A crimper is the proper tool for fixing an improperly terminated RJ45 connection.