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. What file is used to maintain custom parameters for the kernel during system boot?
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
The /var/log/audit/audit.log file contains all policy violations.
browseable option
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.

2. What command can you use to create a file system?
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.
browseable option
mkfs.ext4
The /etc/fstab file.

3. What command is used to change the mail server from Sendmail to Postfix (useful only if you have both installed)?
alternatives --config mta
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
kickstart installations to work
The smbpasswd command is used to create Samba users.

4. What happens if you call the command from question 3 with the -c option after it has already been run?
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
chkconfig—list
For Apache to run a secure site - the mod_ssl package is required to be installed.
By using centralized authentication - you don't need to re-create or maintain multiple accounts across every system in your organization.

5. What command can you use to manage system services?
Sendmail
The service command is used to start - stop - and manage system services.
choose which mode you'd like it to operate in
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.

6. What directory is used to represent the virtual file system created by the kernel?
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
A user's home directory is created under the /home directory.
The anonymous_enable=YES option in the main config file allows anonymous uploads.
By default - Squid runs on port 3128.

7. What command can you use to get information about logical volumes?
Using the host option in the dhcpd.conf file allows you to reserve a client IP address based on its MAC address.
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.
lvdisplay
By default - Squid runs on port 3128.

8. Are additional packages besides httpd required for a secure website - If so - what are they?
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 dig - host - and ping commands can be used to test DNS server functionality.
For Apache to run a secure site - the mod_ssl package is required to be installed.

9. What command (and options) can be used to create a user named George with the description "Jr Admin"?
useradd -c "Jr Admin" George
The service command is used to start - stop - and manage system services.
run on any port you'd like (provided that port is available)
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.

10. What is the difference between the update (-U) and install (-i) options when using rpm to update the kernel?
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.
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.
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
support for TCP Wrappers

11. Can you name three utilities that can be used for network or DNS client troubleshooting?
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
A user's home directory is created under the /home directory.
The three utilities are: route - ping - and nslookup.

12. What are the two types of back-end authentication mechanisms discussed in this chapter?
used for kickstart and/or network installs
This chapter described tdbsm and smbpasswd back-end authentication.
export one or all resources
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.

13. What port does the rndc utility listen on by default?
By default - the rndc utility listens on port 953.
Enforcing during installation
Enforcing during installation
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.

14. A service needs to have _______________ to be able to use it.
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.
support for TCP Wrappers
The smbpasswd command is used to create Samba users.
entering rescue mode and repairing the problem.

15. What is a swap? Is it created as a partition or device file?
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.
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
The du and df commands are used to view available space on the system.
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.

16. How do you run a command with elevated privileges?
When you exit the parted utility - all your changes are automatically written to disk. With the fdisk command - you need to manually write your changes to disk for them to take effect.
You can use the sudo command to run a command with elevated privileges provided you have the rights in the /etc/sudoers file.
chkconfig—list
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.

17. What port does the DHCP server listen on by default?
You add your action to the end of the /home/user01/.bashrc file.
lvdisplay
The DHCP server listens on port 67 by default.
SELinux provides enhanced granular security for the Linux operating system.

18. What two commands are used for package management?
When the system starts up again - the cron service will run any jobs that were missed while the system was off. On Red Hat Enterprise Linux 5 - the anacron service handles this functionality.
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.
The yum and rpm commands are used for package management.
Enforcing during installation

19. What command can you use to view system processes and their CPU usage?
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
Use the ps command to view processes and their CPU usage.
Physical volumes - volume groups - and logical volumes.
chcon

20. How would you disable SELinux protection for NFS - allowing shares to be read/write?
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.
Enforcing during installation
setsebool -P nfs_export_all_rw=1
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.

21. What is the xinetd service used for?
When you exit the parted utility - all your changes are automatically written to disk. With the fdisk command - you need to manually write your changes to disk for them to take effect.
getsebool -a | grep http
Use the route command with the add option to create a static route.
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.

22. What command can you use to monitor and troubleshoot network connections?
The tcpdump command is used to monitor network connections on different interfaces.
The DHCP server listens on port 67 by default.
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
Use the top command to view CPU and memory usage.

23. The ____________ is available for each share.
browseable option
This chapter described tdbsm and smbpasswd back-end authentication.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
The DHCP server listens on port 67 by default.

24. What commands can you use to add a client machine to an LDAP server?
serve both files and printers to users
kickstart installations to work
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.
You can use the authconfig-tui command or the authconfig command.

25. Most boot issues can be resolved by...
entering rescue mode and repairing the problem.
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.
This command reboots virtual guest Client04.

26. What command is used to create a user for Samba?
The nfsstat command can be used to view NFS statistics.
The smbpasswd command is used to create Samba users.
chkconfig sshd off
The htpasswd command can be used to password-protect a web page.

27. What is the benefit of using public/private key authentication?

28. Before you work with quotas - what do you need to do to the file system?
A user's home directory is created under the /home directory.
The smbpasswd command is used to create Samba users.
This chapter described tdbsm and smbpasswd back-end authentication.
The file system where quotas will be implemented must be mounted with the usrquota and grpquota options before quotas will work properly.

29. What command can you use to check the config file of the DHCP server?
By using centralized authentication - you don't need to re-create or maintain multiple accounts across every system in your organization.
service dhcpd configtest
Sendmail
Use the yum groupinstall command to install multiple packages in a single group at once.

30. What protocols are used with Dovecot?
used for kickstart and/or network installs
ifconfig
Use the top command to view CPU and memory usage.
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.

31. Explain the difference between soft and hard limits in quotas.

32. Where are Yum repository config files located?
You must open TCP ports 20 and 21 for the FTP server to function properly.
The three utilities are: route - ping - and nslookup.
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.
Use the top command to view CPU and memory usage.

33. What command can be used to easily list all the options in the FTP main config file?
Apache uses port 80 for HTTP and port 443 for HTTPS.
LUKS encryption
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.
The file system where quotas will be implemented must be mounted with the usrquota and grpquota options before quotas will work properly.

34. What three commands can you use to help verify that the DNS server is functioning properly?
By default - Squid runs on port 3128.
The vsftpd package is used to install an FTP server.
entering rescue mode and repairing the problem.
The dig - host - and ping commands can be used to test DNS server functionality.

35. What command-line program can you use to check your mail?
run on any port you'd like (provided that port is available)
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.
Typing the mail or mutt command allows you to read mail from the command line.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.

36. The portmap service was replaced by the ______________ in Red Hat Enterprise Linux 6.
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
rpcbind service
The service command is used to start - stop - and manage system services.

37. What is the difference between an ext2 and ext3 file system?

38. What command can you use to create a password-protected page?
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
The htpasswd command can be used to password-protect a web page.
chcon
By default - Squid runs on port 3128.

39. The default SMTP service has been changed from _________ to Postfix in Red Hat Enterprise Linux 6.
choose which mode you'd like it to operate in
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
Sendmail
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.

40. Runlevel 0 ___________. Runlevel 6 reboots the system.
The file system where quotas will be implemented must be mounted with the usrquota and grpquota options before quotas will work properly.
halts the system
The htpasswd command can be used to password-protect a web page.
The /etc/fstab file.

41. What benefit does a web proxy provide to your network?
getsebool -a | grep http
A virtual host is a way of hosting multiple sites using a single IP address.
A web proxy can provide multiple benefits - including security - web page caching for faster load times - and load balancing.
You must open TCP ports 20 and 21 for the FTP server to function properly.

42. What is the /etc/vsftpd/user_list file used for?
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
SELinux Booleans provide restrictions to different aspects of a service.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.
The user_list file can be used to limit which users have access to the FTP server.

43. What command can you use to view mounted Samba shares?
The vsftpd package is used to install an FTP server.
The smbstatus command shows you currently mounted Samba resources.
The NFS service uses TCP port 2049 by default.
service sshd statuts

44. Do you need to write changes to the disk when using the parted command? What about fdisk?
You must open TCP ports 20 and 21 for the FTP server to function properly.
Use the ps command to view processes and their CPU usage.
When you exit the parted utility - all your changes are automatically written to disk. With the fdisk command - you need to manually write your changes to disk for them to take effect.
The htpasswd command can be used to password-protect a web page.

45. What command can you use to query information from the kernel about RAID arrays?
The /etc/exports file needs to contain any directory that you want to export - including which options you'd like to use as well.
entering rescue mode and repairing the problem.
cat /proc/mdstat
support for TCP Wrappers

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

47. Which file contains all messages generated during installation that can be used for troubleshooting if the need arises?
The anonymous_enable=YES option in the main config file allows anonymous uploads.
The install.log.syslog file contains messages that are generated during the installation. If you run into trouble during the installation - this is a good place to start.
Apache uses port 80 for HTTP and port 443 for HTTPS.
Use the route command with the add option to create a static route.

48. You must dictate the ____________ you want allocated to your virtual machine when you create it.
amount of RAM
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.
The testparm command allows you to check for syntax errors in the /etc/samba/smb.conf file.
VNC is used to control a remote desktop session.

49. What is the main config file for the DHCP service?
LUKS encryption
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.
The two main config files are master.cf and main.cf.
alternatives --config mta

50. What option would you use to query an installed package using the rpm command?
LUKS encryption
lvdisplay
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.
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.