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. Can you name three utilities that can be used for network or DNS client troubleshooting?
The three utilities are: route - ping - and nslookup.
The -t nfs option is used with the mount command to mount NFS resources.
The smbstatus command shows you currently mounted Samba resources.
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.

2. How can you check the currently mounted file systems?
LUKS encryption
The mount command lists all currently mounted file systems.
You must open TCP ports 20 and 21 for the FTP server to function properly.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.

3. What is the default port that Squid runs on?
The rndc utility provides a method for managing the DNS server remotely and securely.
By default - Squid runs on port 3128.
kickstart installations to work
A user's home directory is created under the /home directory.

4. What does the following firewall rule accomplish: iptables -I INPUT 5 -p tcp -m tcp --dport 80 -j ACCEPT?
getfacl
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.
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.

5. What commands can you use to add a client machine to an LDAP server?
You can use the authconfig-tui command or the authconfig command.
Sendmail
entering rescue mode and repairing the problem.
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514

6. What options with the yum command would you use to remove a package?
cat /proc/mdstat
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
You can use the remove or erase options with yum to remove a package.

7. What command can you use to create your own repositories?
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
The nfsstat command can be used to view NFS statistics.
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.
createrepo

8. What command is used to change the mail server from Sendmail to Postfix (useful only if you have both installed)?
chcon
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
Apache uses port 80 for HTTP and port 443 for HTTPS.
alternatives --config mta

9. What is PAM used for?
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.
The three utilities are: route - ping - and nslookup.
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.
By defining a %post section - you can run scripts after a kickstart installation is complete.

10. What is a virtual host?
A virtual host is a way of hosting multiple sites using a single IP address.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
The three utilities are: route - ping - and nslookup.
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.

11. What option needs to be used with the mount command to mount an NFS resource?
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.
Use the yum groupinstall command to install multiple packages in a single group at once.
The -t nfs option is used with the mount command to mount NFS resources.
schedule one-time-only jobs

12. What is the top command used for?
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
Use the top command to view CPU and memory usage.
Enforcing during installation
You must open TCP ports 20 and 21 for the FTP server to function properly.

13. What command can you use to view NFS statistics?
Using the chcon command - you can change the context of a file to work with Apache.
The yum and rpm commands are used for package management.
You can use the authconfig-tui command or the authconfig command.
The nfsstat command can be used to view NFS statistics.

14. Which log file is used to keep track of policy violations?
The smbpasswd command is used to create Samba users.
The /var/log/audit/audit.log file contains all policy violations.
The virsh command is used to manage virtual guests.
service dhcpd configtest

15. How can you list all services on the system to tell whether they will boot during startup?
setsebool -P nfs_export_all_rw=1
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.
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.

16. What protocols are used with Dovecot?
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.
chkconfig—list
The vsftpd package is used to install an FTP server.
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.

17. What does the rdnc-confgen command do?
The htpasswd command can be used to password-protect a web page.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.
The rdnc-confgen command generates an rndc.conf file for the rndc utility.

18. To create a RAID or LVM partition using kickstart
Kickstart supports both basic and advanced partitioning (RAID/LVM).
The rpm command can operate in install - query - or verify modes.
VNC is used to control a remote desktop session.
The NFS service uses TCP port 2049 by default.

19. What are the three different types of RAID described in this chapter?
service httpd configtest
By default - the rndc utility listens on port 953.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
The -t nfs option is used with the mount command to mount NFS resources.

20. The INPUT chain being used is the default under Red Hat Enterprise Linux 5. This rule...
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
generates errors under Red Hat Enterprise Linux 6
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
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.

21. What is a swap? Is it created as a partition or device file?
support TCP Wrappers
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.
used for kickstart and/or network installs
getsebool -a | grep http

22. What are the two types of back-end authentication mechanisms discussed in this chapter?
By default - Squid runs on port 3128.
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
This chapter described tdbsm and smbpasswd back-end authentication.
used for kickstart and/or network installs

23. In Red Hat Enterprise Linux 6 - the default for SELinux is _______________ (which can be changed after the installation completes). For Red Hat Enterprise Linux 5 - you were able to choose what mode you wanted SELinux to start in.
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
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.
Enforcing during installation

24. How would you view all Boolean options for the HTTP service?
getsebool -a | grep http
DNS uses port 53.
An ext3 file system has journaling built in to it - whereas the ext2 file system doesn't.
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.

25. How would you go about creating a static route?
Use the route command with the add option to create a static route.
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 service command is used to start - stop - and manage system services.
useradd -c "Jr Admin" George

26. What critical step must you take after updating the kernel to a newer version?
The SMTP service runs on TCP port 110.
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.
Using the chcon command - you can change the context of a file to work with Apache.
service named configtest

27. What is the biggest benefit to using LVM over basic partitions?
The rdnc-confgen command generates an rndc.conf file for the rndc utility.
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.
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.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.

28. What command is used to create a user for Samba?
Network address translation (NAT) maintains a table that allows the use of multiple internal IP addresses to a multiple public IP address (called address translation). It can also be used for one-to-one or one-to-many relationships as well.
The smbpasswd command is used to create Samba users.
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 xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.

29. How do you run a command with elevated privileges?
You can use the sudo command to run a command with elevated privileges provided you have the rights in the /etc/sudoers file.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
The rdnc-confgen command generates an rndc.conf file for the rndc utility.
The anonymous_enable=YES option in the main config file allows anonymous uploads.

30. Red Hat Enterprise Linux 6 is the only version that officially supports _______
You can use the authconfig-tui command or the authconfig command.
The lftp command can be used on a client to test FTP server connections.
LUKS encryption
service httpd configtest

31. Is it possible to share files among groups - What permissions would you set on the directory to accomplish file sharing if possible?
Use the setgid flag to create the appropriate permissions (chmod 2770).
The nfsstat command can be used to view NFS statistics.
Use the route command with the add option to create a static route.
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.

32. Runlevel 0 ___________. Runlevel 6 reboots the system.
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
halts the system
Sendmail
chcon

33. What is the difference between the update (-U) and install (-i) options when using rpm to update the kernel?
chkconfig xinetd --list
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.
mkfs.ext4
A user's home directory is created under the /home directory.

34. By default - what is the path to a user's home directory?

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35. What is the last rule in the iptables file?

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36. What is the name of the package used to install an FTP?
Use the top command to view CPU and memory usage.
The ping command can be used to verify connectivity to another host.
The TFTP server uses UDP port 69.
The vsftpd package is used to install an FTP server.

37. What is the format of the /etc/shadow file?
service sshd statuts
entering rescue mode and repairing the problem.
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.

38. Do you need to write changes to the disk when using the parted command? What about fdisk?
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.
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.
useradd -c "Jr Admin" George
The htpasswd command can be used to password-protect a web page.

39. What command can you use to view system processes and their CPU usage?
atq
The mount command lists all currently mounted file systems.
Use the ps command to view processes and their CPU usage.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.

40. What command can you use to query Boolean values?
defining a %pre section although it is rarely used
entering rescue mode and repairing the problem.
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.
getsebool

41. Which remote management service is installed by default?Can you name the port that it uses?
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.
halts the system
getsebool
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.

42. What is the point of using SELinux?
This chapter described tdbsm and smbpasswd back-end authentication.
SELinux provides enhanced granular security for the Linux operating system.
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.
Use the top command to view CPU and memory usage.

43. What command displays your current interfaces and IP address?
service named configtest
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.
ifconfig
The VNC package for Red Hat Enterprise Linux 6 is tiger-vnc.

44. What command is used to show all services being controlled by the xinetd daemon?
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
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
chkconfig xinetd --list
DNS uses port 53.

45. What option is used to allow anonymous uploads to the FTP server?
getfacl
The service command is used to start - stop - and manage system services.
The anonymous_enable=YES option in the main config file allows anonymous uploads.
Version 2 is the latest and most secure version of SSH.

46. What command and options can you use to update the time?
DNS uses port 53.
The two main config files are master.cf and main.cf.
After the ntpd service is stopped - you can use the ntpdate <server> command to update/sync the time.
The smbstatus command shows you currently mounted Samba resources.

47. Which file contains all messages generated during installation that can be used for troubleshooting if the need arises?
The /var/lib/nfs/etab file is used to keep track of currently exported resources.
useradd -c "Jr Admin" George
service httpd configtest
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.

48. The virt-install package allows you to manage virtual machines _____________. The virt-manager package allows you to manage virtual machines via a GUI interface.
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 htpasswd command can be used to password-protect a web page.
via the command line
repquota

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

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50. What is the difference between an A record and a PTR record?
createrepo
An ext3 file system has journaling built in to it - whereas the ext2 file system doesn't.
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.
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.