A systems administrator wants to permit access temporarily to an application running on port 1234/TCP on a Linux server. Which of the following commands will permit this traffic?
Correct Answer:
C
The firewall-cmd command is used to manage firewalld, which is a firewall service for Linux systems that provides dynamic and persistent configuration of firewall rules. Firewalld uses zones and services to define different levels of trust and access for network connections.
To permit access temporarily to an application running on port 1234/TCP on a Linux server, the systems administrator can use the firewall-cmd --add-port=1234/tcp command. This command will add a rule to the default zone (usually public) that allows incoming traffic on port 1234/TCP. The rule will only be effective until the next reload or restart of firewalld. To make the rule permanent, the administrator can add the --permanent option to the command. The statement C is correct.
The statements A, B, and D are incorrect because they do not permit access to port 1234/TCP. The firewall-cmd --new-service=1234/tcp command does not exist. The firewall- cmd --service=1234 --protocol=tcp command does not work because 1234 is not a predefined service name in firewalld. The firewall-cmd --add-whitelist-uid=1234 command does not exist. References: [How to Use FirewallD to Manage Firewall in Linux]
DRAG DROP
As a Systems Administrator, to reduce disk space, you were tasked to create a shell script that does the following:
Add relevant content to /tmp/script.sh, so that it finds and compresses rotated files in
/var/log without recursion. INSTRUCTIONS
Fill the blanks to build a script that performs the actual compression of rotated log files.
If at any time you would like to bring back the initial state of the simulation, please click the Reset All button.
Solution:
Does this meet the goal?
Correct Answer:
A
A Linux administrator was tasked with deleting all files and directories with names that are contained in the sobelete.txt file. Which of the following commands will accomplish this task?
Correct Answer:
D
The command cat toDelete.txt | xargs rm -rf will delete all files and directories with names that are contained in the toDelete.txt file. The cat command reads the file and outputs its contents to the standard output. The | operator pipes the output to the next command. The xargs command converts the output into arguments for the next command. The rm -rf command removes the files and directories recursively and forcefully. This is the correct way to accomplish the task. The other options are incorrect because they either use the wrong options (-f instead of -a for xargs), the wrong arguments (toDelete.txt instead of toDelete.txt filename for rm), or the wrong commands (rm instead of xargs). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 11: Managing Files and Directories, pages 349-350.
A user is asking the systems administrator for assistance with writing a script to verify whether a file exists. Given the following:
Which of the following commands should replace the
Correct Answer:
A
The command if [ -f "$filename" ]; then checks if the variable $filename refers to a regular file that exists. The -f option is used to test for files. If the condition is true, the commands after then are executed. This is the correct way to replace the <CONDITIONAL> string. The other options are incorrect because they either use the wrong option (-d tests for directories), the wrong syntax (missing a semicolon after the condition), or the wrong keyword (while is used for loops, not conditions). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 16: Writing and Executing Bash Shell Scripts, page 493.
A systems administrator wants to test the route between IP address 10.0.2.15 and IP address 192.168.1.40. Which of the following commands will accomplish this task?
Correct Answer:
B
The command ip route get 192.168.1.40 from 10.0.2.15 will test the route between the IP address 10.0.2.15 and the IP address 192.168.1.40. The ip route get command shows the routing decision for a given destination and source address. This is the correct command to accomplish the task. The other options are incorrect because they either use the wrong commands (route instead of ip route), the wrong options (-e or - n instead of get), or the wrong syntax (to instead of from). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 379.