FirstTry

Objective 5.4

220-1201

Given a scenario, troubleshoot common mobile device issues.

Objective 5.4 sits in Hardware and Network Troubleshooting, which carries 28% of the A+ Core 1 exam. The questions below are original, written from the official objective title above, and each explanation cites the CompTIA page it rests on.

Objective title verbatim from the official objectives. CompTIA exam page ↗

A worked example

Shown solved, with the whole explanation open: this is what every question here carries.

5-4Hardware and Network Troubleshooting

A technician captures traffic from a tablet that suddenly stops responding to a file server. The capture shows a session end with the RST flag set to 1 and all connection details erased immediately. What does this indicate?

An abrupt TCP reset that ends the session and erases the connection infoCorrect · your answerCorrect: this is the only closure type that erases connection info immediately.
A graceful four-way closure that both endpoints agreed to performA graceful four-way close is marked by FIN, not RST, and tears the connection down in order without discarding it abruptly.
The normal TIME_WAIT state that follows a graceful closureTIME_WAIT is the wait after a clean close that lets stray packets drain; it holds state rather than erasing it.
A successful three-way handshake completing the connection setupA three-way handshake opens a session and shows SYN and SYN-ACK; an RST is the opposite of setup.

Correct.

Checked against learn.microsoft.com, July 2026

Concept

TCP sessions can end either gracefully through a four-way closure or abruptly through a reset, and the two are distinguishable by which flag is set.

Why A

An RST flag set to 1 signals an abrupt session closure, which immediately releases resources and erases all connection information, matching the behavior seen in the capture.

Source

A TCP reset is an abrupt session closure, causing the immediate release of allocated resources and erasure of all connection information. This is identified by setting the RESET flag in the TCP header to 1.

Microsoft Learn: Troubleshoot TCP/IP connectivity, checked July 2026
#mobile devices#connectivity#tcp

Now you: objective 5.4 questions

No account needed. The explanation opens when you answer.

Sample question 1 of 3

5-4Hardware and Network Troubleshooting

A user's smartphone finishes a file transfer with a corporate server and closes the connection gracefully. A technician notes the port stays reserved for several minutes afterward. What is this default wait state called, and how long does it typically last?

Sample question 2 of 3

5-4Hardware and Network Troubleshooting

An employee's phone cannot sync corporate email. A packet capture on the phone shows a TCP SYN retransmitted three times with no reply, while a simultaneous capture at the server shows none of those SYN packets arriving. What does this most likely indicate?

Sample question 3 of 3

5-4Hardware and Network Troubleshooting

A tablet's SYN packets reach the mail server during a sync attempt, but the server never responds. A technician wants to confirm whether the destination port is actually listening. Which command should be run on the server?

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Read the sources

These are the official pages the questions above cite. Reading them is studying the objective from the primary source, which is what the explanations point you toward anyway.

More objectives in Hardware and Network Troubleshooting