Test your basic knowledge |

RHCSA

Subjects : certifications, it-skills, rhcsa

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Should you allow remote root access - Why or why not?

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2. What option needs to be used with the mount command to mount an NFS resource?
By default - Squid runs on port 3128.
If you are a hosting company or want to run multiple websites/applications from a single IP address - you can use virtual hosts to accomplish this.
The -t nfs option is used with the mount command to mount NFS resources.
Public/private key authentication provides an additional layer of security because you need the correct key instead of just knowing someone's password. Passwords combined with public/private keys take the security one additional step.

3. Which file shows you all the client IP addresses?
The /var/log/audit/audit.log file contains all policy violations.
createrepo
Physical volumes - volume groups - and logical volumes.
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.

4. What command is used to change the mail server from Sendmail to Postfix (useful only if you have both installed)?
defining a %pre section although it is rarely used
A web proxy can provide multiple benefits - including security - web page caching for faster load times - and load balancing.
SELinux provides enhanced granular security for the Linux operating system.
alternatives --config mta

5. What is the default port that Squid runs on?
entering rescue mode and repairing the problem.
serve both files and printers to users
You can use the -q option to query an installed package. Combining grep and the -qa options - you can search among all installed packages on the system.
By default - Squid runs on port 3128.

6. Can you name the two commands that can be used to view the free space on the system?
service httpd configtest
The du and df commands are used to view available space on the system.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.
enabled by default

7. What happens if you call the command from question 3 with the -c option after it has already been run?
Enforcing during installation
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
browseable option
The rpm command can operate in install - query - or verify modes.

8. What option at the GRUB boot menu can you use to append something to a kernel?
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
choose which mode you'd like it to operate in
A user's home directory is created under the /home directory.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.

9. What is a gateway used for on a network?
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
The TFTP server uses UDP port 69.
A gateway is used as an entry and exit point for a subnet on a network. To contact hosts outside your subnet - you need to pass through a gateway.
Use the setgid flag to create the appropriate permissions (chmod 2770).

10. What critical step must you take after updating the kernel to a newer version?
The -t nfs option is used with the mount command to mount NFS resources.
You must ensure that the /boot/grub/grub.conf file has the new entry for your newly updated kernel to be able to boot into it.
This command reboots virtual guest Client04.
The SMTP service runs on TCP port 110.

11. What options with the yum command would you use to remove a package?
You can use the remove or erase options with yum to remove a package.
This is actually a trick question because the answer could go either way. In this chapter - we discussed only software RAID setups - in which case the answer is no. If - however - you were using a hardware RAID 5 - the answer would be yes.
rpmbuild
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.

12. Before you work with ACLs - what do you need to do to the file system?
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
The two main config files are master.cf and main.cf.
A soft limit acts like an alarm - signaling you when you are reaching your limit. If you don't specify a grace period - the soft limit is the max. A hard limit is required only when a grace period exists. It is the max limit you can hit before your g

13. What is the format of the /etc/shadow file?
alternatives --config mta
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
A user's home directory is created under the /home directory.
ifconfig

14. What port does the DHCP server listen on by default?
The /etc/hosts file is a local lookup file used to map IP addresses to hostnames if a DNS server isn't available.
The virsh command is used to manage virtual guests.
If you are a hosting company or want to run multiple websites/applications from a single IP address - you can use virtual hosts to accomplish this.
The DHCP server listens on port 67 by default.

15. The package selection screen allows you to install any software you want during the installation process as long as...
SELinux Booleans provide restrictions to different aspects of a service.
ifconfig
you have access to the correct packages or repositories.
You should never allow remote root access. Should your root account become compromised and you use the same password - someone could gain access to all your systems. You also don't want the most powerful user of your system (with no accountability) l

16. What is the xinetd service used for?
entering rescue mode and repairing the problem.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.

17. What are the two types of back-end authentication mechanisms discussed in this chapter?
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
The nfsstat command can be used to view NFS statistics.
This chapter described tdbsm and smbpasswd back-end authentication.

18. How can you change the security context of a directory to work with Apache?
A swap is scratch space on your file system used as virtual memory. A swap can be created as a partition or a device file.
Using the chcon command - you can change the context of a file to work with Apache.
The rpm command can operate in install - query - or verify modes.
The four types of DNS servers are master - slave - caching-only - and forwarding.

19. How would you view all Boolean options for the HTTP service?
Network installations can be performed using the HTTP - FTP - and NFS protocols.
generates errors under Red Hat Enterprise Linux 6
The du and df commands are used to view available space on the system.
getsebool -a | grep http

20. What command would you use to create a group - to add the user George to the group?
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
Stage 1: During this stage - the primary bootloader is read into memory by the BIOS from the MBR. Stage 1.5: During this stage - the bootloader is read into memory by the stage 1 bootloader (only if necessary). Stage 2: During this stage - the bootlo
Use the groupadd command to create a group. You can then add user George with the following: usermod -G <group name> George

21. What command and option can you use to enable a service to start on boot?
halts the system
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.
You must ensure that the /boot/grub/grub.conf file has the new entry for your newly updated kernel to be able to boot into it.

22. What are the three items that make up LVM?
Physical volumes - volume groups - and logical volumes.
You have the flexibility to resize and add new volumes on the fly. With basic partitions - any time that you want to make a change - you need to destroy the partition and create it again.
This command reboots virtual guest Client04.
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514

23. What is a virtual host?
A swap is scratch space on your file system used as virtual memory. A swap can be created as a partition or a device file.
rpcbind service
A virtual host is a way of hosting multiple sites using a single IP address.
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.

24. There are four types of DNS servers. Name them.
The four types of DNS servers are master - slave - caching-only - and forwarding.
After the ntpd service is stopped - you can use the ntpdate <server> command to update/sync the time.
By defining a %post section - you can run scripts after a kickstart installation is complete.
A virtual host is a way of hosting multiple sites using a single IP address.

25. What are the two config files for Postfix called?
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.
Kickstart supports both basic and advanced partitioning (RAID/LVM).
The two main config files are master.cf and main.cf.

26. What two ports should be opened on the firewall for the FTP server to function properly?
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.
The /etc/hosts file is a local lookup file used to map IP addresses to hostnames if a DNS server isn't available.
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
You must open TCP ports 20 and 21 for the FTP server to function properly.

27. Runlevel 0 ___________. Runlevel 6 reboots the system.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
Use the yum groupinstall command to install multiple packages in a single group at once.
A web proxy can provide multiple benefits - including security - web page caching for faster load times - and load balancing.
halts the system

28. What command is used to create an RPM package?
setsebool -P nfs_export_all_rw=1
The -t nfs option is used with the mount command to mount NFS resources.
A gateway is used as an entry and exit point for a subnet on a network. To contact hosts outside your subnet - you need to pass through a gateway.
rpmbuild

29. SSH does...
support TCP Wrappers
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.
The nfsstat command can be used to view NFS statistics.
The tcpdump command is used to monitor network connections on different interfaces.

30. What command can you use to check the config file of the DHCP server?
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
service dhcpd configtest
The nfsstat command can be used to view NFS statistics.
SELinux Booleans provide restrictions to different aspects of a service.

31. What command can you use to test the config files before starting the DNS service?
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
service named configtest
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
The /var/log/audit/audit.log file contains all policy violations.

32. What are the five required directories when building RPMS?
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
Physical volumes - volume groups - and logical volumes.
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.

33. What file is used to maintain custom parameters for the kernel during system boot?
atq
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
PAM is used as a modular way to leverage security. In this chapter - the main function we discussed was for managing password policies and complexity.

34. What does the following firewall rule accomplish: iptables -I INPUT 5 -p tcp -m tcp --dport 80 -j ACCEPT?
The firewall rule is inserted into the fifth line of the iptables rules and opens up TCP port 80 (for the HTTP service) on the firewall to allow incoming connections.
support TCP Wrappers
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
alternatives --config mta

35. What command can you use to create a password-protected page?
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.
ifconfig
The htpasswd command can be used to password-protect a web page.
repquota

36. What command can you use to view system processes and their CPU usage?
You can use the -q option to query an installed package. Combining grep and the -qa options - you can search among all installed packages on the system.
Use the ps command to view processes and their CPU usage.
enabled by default
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.

37. What are the three different types of RAID described in this chapter?
mkfs.ext4
atq
Using the chcon command - you can change the context of a file to work with Apache.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).

38. What is the difference between the update (-U) and install (-i) options when using rpm to update the kernel?
You should never use the -U option because it erases the prior kernel when updating. This leaves you with no fallback kernel should your system not boot properly.
The three utilities are: route - ping - and nslookup.
rpcbind service
Use the resize2fs command to grow a file system.

39. What is the /etc/hosts file used for?

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40. What command can you use to query information from the kernel about RAID arrays?
Public/private key authentication provides an additional layer of security because you need the correct key instead of just knowing someone's password. Passwords combined with public/private keys take the security one additional step.
The service command is used to start - stop - and manage system services.
For Apache to run a secure site - the mod_ssl package is required to be installed.
cat /proc/mdstat

41. What does the partprobe command do?
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
rpcbind service
getsebool
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.

42. What command disables the SSH service from running when the system boots?
Use the route command with the add option to create a static route.
chkconfig sshd off
The anonymous_enable=YES option in the main config file allows anonymous uploads.
You can use the -q option to query an installed package. Combining grep and the -qa options - you can search among all installed packages on the system.

43. If you want a specific action to take place when user01 logs in to the system - which file would you edit?
The nfsstat command can be used to view NFS statistics.
The SMTP service runs on TCP port 110.
You add your action to the end of the /home/user01/.bashrc file.
The yum and rpm commands are used for package management.

44. What does it mean if you ping a host and you receive the response Destination Unreachable?
cat /proc/mdstat
Yum repository config files (.repo files) are located in the /etc/yum.repos.d directory. You can also make direct entries into the main /etc/yum.conf file.
The tcpdump command is used to monitor network connections on different interfaces.
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.

45. Which remote management service is installed by default?Can you name the port that it uses?
The rpm command can operate in install - query - or verify modes.
By default - the rndc utility listens on port 953.
The SSH service is almost always installed by default in Red Hat. It uses TCP port 22 - and this port is open on the default firewall rules.
Sendmail

46. Is it possible to share files among groups - What permissions would you set on the directory to accomplish file sharing if possible?
load balancing and redundancy benefits
used for kickstart and/or network installs
Use the setgid flag to create the appropriate permissions (chmod 2770).
choose which mode you'd like it to operate in

47. GRUB has three stages. Can you name them?
Stage 1: During this stage - the primary bootloader is read into memory by the BIOS from the MBR. Stage 1.5: During this stage - the bootloader is read into memory by the stage 1 bootloader (only if necessary). Stage 2: During this stage - the bootlo
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
support for TCP Wrappers

48. You must dictate the ____________ you want allocated to your virtual machine when you create it.
The yum and rpm commands are used for package management.
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
LUKS encryption
amount of RAM

49. What are SELinux Booleans?
A gateway is used as an entry and exit point for a subnet on a network. To contact hosts outside your subnet - you need to pass through a gateway.
Public/private key authentication provides an additional layer of security because you need the correct key instead of just knowing someone's password. Passwords combined with public/private keys take the security one additional step.
You should never allow remote root access. Should your root account become compromised and you use the same password - someone could gain access to all your systems. You also don't want the most powerful user of your system (with no accountability) l
SELinux Booleans provide restrictions to different aspects of a service.

50. How would you install a group of packages all at a single time?
Physical volumes - volume groups - and logical volumes.
Use the yum groupinstall command to install multiple packages in a single group at once.
The chmod command is used to change the permissions of files and directories. The chown command is used to change the ownership of files and directories.
The /var/lib/nfs/etab file is used to keep track of currently exported resources.