FirstTry
Objective 4.2XK0-005

4.2 Given a scenario, analyze and troubleshoot network resource issues.

Objective 4.2 sits in Troubleshooting, which carries 28% of the Linux+ 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.

4-2TroubleshootingModerate

An administrator finds a new service will not bind to port 8080 because something already holds it. Which command shows the listening process on that port?

ping -c 1 localhostping tests reachability with ICMP, not which process owns a port.
ss -tlnpCorrect · your answerCorrect: -t -l -n -p lists the listening TCP socket and its process.
ip route showip route shows routing, not socket ownership.
dig localhostdig queries DNS and says nothing about local ports.

Correct.

Concept

Diagnosing a port conflict means listing listening sockets together with the process that owns each one.

Why B

ss -tlnp shows listening TCP sockets numerically with the owning process, revealing what already holds the port.

Source

#troubleshooting#network#ss

Now you: objective 4.2 questions

No account needed. The explanation opens when you answer.

Sample question 1 of 3

4-2TroubleshootingHard

An administrator runs:

$ ss -tlnp
State  Local Address:Port  Process
LISTEN 0.0.0.0:22          users:(("sshd",pid=812))
LISTEN 127.0.0.1:5432      users:(("postgres",pid=990))

Which service accepts connections from other hosts?

Sample question 2 of 3

4-2TroubleshootingHard

An administrator finds ping 8.8.8.8 succeeds but ping example.com fails with 'Name or service not known'. What is the likely cause?

Sample question 3 of 3

4-2TroubleshootingModerate

After the DNS server IP changed, name lookups fail on a host. Which file's nameserver line does the administrator correct?

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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 Troubleshooting