CompTIA CompTIA Certifications XK0-004 Questions & Answers

• Question 191:

  A Linux administrator needs to generate SSH keys for remote users. The company security policy requires at least 4096-bit encryption on all public/private key pairs. Which of the following commands should the administrator issue to comply with company policy?

  A. ssh-keygen -c 4096

  B. ssh-keygen -b 4096

  C. ssh-keygen -t rsa

  D. ssh-keygen -t dsa

  Correct Answer: C

  Reference: https://www.ssh.com/academy/ssh/keygen

• Question 192:

  Which of the following commands would a junior systems administrator run to monitor network traffic actively?

  A. netstat

  B. nmap

  C. ping

  D. tcpdump

  Correct Answer: A

  Reference: https://bytexd.com/19-commands-to-monitor-the-network-activity-in-linux/

• Question 193:

  A user sent the following log to the help desk:

  

  Which of the following should the help desk technician do to resolve this issue?

  A. chmod 700 /home/user02/.ssh

  B. chown -R user01 /home/user02

  C. chmod u+x /home/user02

  D. chmod 600 /home/user02/.bash_profile

  Correct Answer: A

• Question 194:

  Which of the following files would a junior systems administrator check to verify DNS server settings?

  A. /etc/network

  B. /etc/resolv.conf

  C. /etc/nsswitch.conf

  D. /etc/hosts

  Correct Answer: B

  Reference: https://www.tecmint.com/find-my-dns-server-ip-address-in-linux/

• Question 195:

  An administrator is troubleshooting an issue where end users are waiting a very long time for processes to respond. The top command reveals that multiple processes seem to be in a non-responsive state or have become zombies. Which of the following commands should the administrator use to clean up the system?

  A. pkill -o 15m

  B. killall -n

  C. pkill -x

  D. killall -o 15m

  Correct Answer: B

• Question 196:

  An administrator needs to ensure the JAVA_HOME variable is set correctly for all users that log in to the server. Which of the following files should be edited to set this variable?

  A. /etc/profile

  B. /etc/skel/.profile

  C. /home/user/.profile

  D. /etc/rc.local

  Correct Answer: A

  Reference: https://stackoverflow.com/questions/24641536/how-to-set-java-home-in-linux-for-all-users

• Question 197:

  A Linux administrator is troubleshooting an issue with a shell script. Users in the accounting department are unable to run the script, but users in the sales department are not having issues. Users in both departments should be able to run the

  script. The administrator checks the permissions on the script and receives the following information:

  -r-xr-xr-- joe sales script.sh

  Which of the following commands should the administrator execute to resolve the problem?

  A. chgrp accounting script.sh

  B. chmod 644 script.sh

  C. chown accounting script.sh

  D. chmod a+x script.sh

  Correct Answer: B

• Question 198:

  A systems engineer was configuring a small, single-board device running Linux when the device lost power during an outage. The device was running an SSH server and was set up to obtain an IP address via DHCP. The engineer does not know the hostname of the device but does know the manufacturer and the network it is on.

  Which of the following would output the MOST useful results when attempting to find the device's IP address?

  A. arp

  B. whois

  C. nmap

  D. ping

  E. netcat

  Correct Answer: A

  Reference: https://www.pcwdld.com/find-device-or-ip-address-using-mac-address

• Question 199:

  A Linux administrator is installing an NGINX-based proxy service on the same server that hosts the Apache-based HTTP services When the administrator launches the proxy service, the following error message is received:

  Address already in use: make_sock: could not bind to address 0.0.0.0:80

  The administrator runs the following commands to troubleshoot the issue and receives the following relevant output:

  

  Which of the following is the MOST likely issue?

  A. A FORWARD chain rule in iptables is missing

  B. An application is using port 80

  C. Apache is only listening on localhost:80

  D. The httpd is missing the proxy module

  Correct Answer: B

• Question 200:

  A storage administrator added a new primary partition to a drive and wants to create a filesystem without rebooting. Which of the following commands will allow this to happen?

  A. fdisk

  B. fsck2

  C. partprobe

  D. parted

  Correct Answer: D

  Reference: https://www.gnu.org/software/parted/manual/html_chapter/parted_2.html