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. Most boot issues can be resolved by...
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
support for TCP Wrappers
entering rescue mode and repairing the problem.
load balancing and redundancy benefits

2. What does it mean if you ping a host and you receive the response Destination Unreachable?
load balancing and redundancy benefits
No. Red Hat Enterprise Linux 6 uses a different key to sign its packages.
you have access to the correct packages or repositories.
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.

3. What is NAT - How is it used?
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.
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.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
The four types of DNS servers are master - slave - caching-only - and forwarding.

4. What is the xinetd service used for?
By default - Squid runs on port 3128.
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.
defining a %pre section although it is rarely used
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.

5. The exportfs command is used to...
The four types of DNS servers are master - slave - caching-only - and forwarding.
export one or all resources
You add your action to the end of the /home/user01/.bashrc file.
load balancing and redundancy benefits

6. What three components are needed to fully automate a kickstart installation?
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
The vsftpd package is used to install an FTP server.
The service command is used to start - stop - and manage system services.
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.

7. What port must be opened on the firewall for DNS?
chkconfig sshd off
defining a %pre section although it is rarely used
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.
DNS uses port 53.

8. The INPUT chain being used is the default under Red Hat Enterprise Linux 5. This rule...
generates errors under Red Hat Enterprise Linux 6
You add your action to the end of the /home/user01/.bashrc file.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.
The rpm command can operate in install - query - or verify modes.

9. What command can you use to create your own repositories?
createrepo
service httpd configtest
The SMTP service runs on TCP port 110.
The -t nfs option is used with the mount command to mount NFS resources.

10. Is it possible to share files among groups - What permissions would you set on the directory to accomplish file sharing if possible?
The tcpdump command is used to monitor network connections on different interfaces.
Version 2 is the latest and most secure version of SSH.
Use the setgid flag to create the appropriate permissions (chmod 2770).
chkconfig xinetd --list

11. What command can be used to view the queue for at service jobs?
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 add your action to the end of the /home/user01/.bashrc file.
A virtual host is a way of hosting multiple sites using a single IP address.
atq

12. What command can you use to check the config file of the DHCP server?
The rpm command can operate in install - query - or verify modes.
service dhcpd configtest
Use the resize2fs command to grow a file system.
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.

13. What is the biggest benefit to using LVM over basic partitions?
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
Enforcing during installation
The tcpdump command is used to monitor network connections on different interfaces.
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.

14. How can you change the security context of a directory to work with Apache?
Using the chcon command - you can change the context of a file to work with Apache.
A user's home directory is created under the /home directory.
By default - the rndc utility listens on port 953.
setsebool -P nfs_export_all_rw=1

15. Does a DHCP server allow reserved IP addresses - If so - how?
The print option is used with both the fdisk and parted commands to display the current partition tables.
ifconfig
Using the host option in the dhcpd.conf file allows you to reserve a client IP address based on its MAC address.
service dhcpd configtest

16. What port does the SMTP service run on?
The user_list file can be used to limit which users have access to the FTP server.
The SMTP service runs on TCP port 110.
For Apache to run a secure site - the mod_ssl package is required to be installed.
The tcpdump command is used to monitor network connections on different interfaces.

17. What does ifconfig 172.168.1.100 netmask 255.255.255.0 eth1 do?
This command sets the eth1 interface to have a static IP address of 172.168.1.100 with a netmask of 255.255.255.0.
The testparm command allows you to check for syntax errors in the /etc/samba/smb.conf file.
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.
You can use the sudo command to run a command with elevated privileges provided you have the rights in the /etc/sudoers file.

18. What command can you use to view the current ACL on a file?
The dig - host - and ping commands can be used to test DNS server functionality.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
getfacl
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.

19. What option needs to be used with the mount command to mount an NFS resource?
The -t nfs option is used with the mount command to mount NFS resources.
The TFTP server uses UDP port 69.
The four types of DNS servers are master - slave - caching-only - and forwarding.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.

20. What port does the DHCP server listen on by default?
setsebool -P nfs_export_all_rw=1
repquota
The DHCP server listens on port 67 by default.
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.

21. What does the testparm command do?
The mount command lists all currently mounted file systems.
Enforcing during installation
Kickstart supports both basic and advanced partitioning (RAID/LVM).
The testparm command allows you to check for syntax errors in the /etc/samba/smb.conf file.

22. Which remote management service is installed by default?Can you name the port that it uses?
The two main config files are master.cf and main.cf.
By default - the rndc utility listens on port 953.
createrepo
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.

23. What is the main config file for the DHCP service?
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.
atq
The vsftpd package is used to install an FTP server.
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.

24. What is the difference between an A record and a PTR record?
DNS uses port 53.
choose which mode you'd like it to operate in
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.
Use the ps command to view processes and their CPU usage.

25. Runlevel 0 ___________. Runlevel 6 reboots the system.
The tcpdump command is used to monitor network connections on different interfaces.
halts the system
SELinux provides enhanced granular security for the Linux operating system.
The rdnc-confgen command generates an rndc.conf file for the rndc utility.

26. What is the default port that Squid runs on?
By default - Squid runs on port 3128.
defining a %pre section although it is rarely used
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
Enforcing during installation

27. What port does NFS use by default?
The NFS service uses TCP port 2049 by default.
A user's home directory is created under the /home directory.
user's home directory in the /etc/skel directory
The virsh command is used to manage virtual guests.

28. How can you list all services on the system to tell whether they will boot during startup?
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
support TCP Wrappers
getsebool -a | grep http
chkconfig—list

29. What command is used to show all services being controlled by the xinetd daemon?
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.
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.
rpmbuild
chkconfig xinetd --list

30. How do you run a command with elevated privileges?
A virtual host is a way of hosting multiple sites using a single IP address.
You can use the sudo command to run a command with elevated privileges provided you have the rights in the /etc/sudoers file.
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.
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.

31. What is the format of the /etc/shadow file?
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 format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
service httpd configtest
The DHCP server listens on port 67 by default.

32. What command is used to change the mail server from Sendmail to Postfix (useful only if you have both installed)?
alternatives --config mta
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.
The dig - host - and ping commands can be used to test DNS server functionality.
SSH is used for secure remote management of Linux systems.

33. What are the side effects of shrinking a volume group or logical volume?
By defining a %post section - you can run scripts after a kickstart installation is complete.
ifconfig
alternatives --config mta
If you shrink a volume group or logical volume - there is a chance you could lose data depending on how much you shrink the volume.

34. What does S12rsyslog in the /etc/rc.d/rc2.d directory mean?
When the system enters into runlevel 2 - the rsyslog service has a priority of 12 when starting. Anything with a lower number (or the same number and lower first letter) starts before the rsyslog service.
An ext3 file system has journaling built in to it - whereas the ext2 file system doesn't.
kickstart installations to work
ifconfig

35. What command can you use to monitor and troubleshoot network connections?
The print option is used with both the fdisk and parted commands to display the current partition tables.
The tcpdump command is used to monitor network connections on different interfaces.
By default - the rndc utility listens on port 953.
user's home directory in the /etc/skel directory

36. Which file contains all messages generated during installation that can be used for troubleshooting if the need arises?
schedule one-time-only jobs
Use the groupadd command to create a group. You can then add user George with the following: usermod -G <group name> George
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.
service sshd statuts

37. What is SSH used for?
Use the groupadd command to create a group. You can then add user George with the following: usermod -G <group name> George
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.
SSH is used for secure remote management of Linux systems.
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.

38. What command can you use to query Boolean values?
getsebool
The four types of DNS servers are master - slave - caching-only - and forwarding.
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.
If you shrink a volume group or logical volume - there is a chance you could lose data depending on how much you shrink the volume.

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

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40. What command disables the SSH service from running when the system boots?
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
chkconfig sshd off
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

41. What is the /var/lib/nfs/etab file used for?
VNC is used to control a remote desktop session.
The /var/lib/nfs/etab file is used to keep track of currently exported resources.
browseable option
The mount command lists all currently mounted file systems.

42. Which version of SSH should you use?
Version 2 is the latest and most secure version of SSH.
load balancing and redundancy benefits
chkconfig xinetd --list
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.

43. How can you display all virtual guests after they're connected to a hypervisor?
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
Typing the mail or mutt command allows you to read mail from the command line.
The anonymous_enable=YES option in the main config file allows anonymous uploads.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.

44. What two ports should be opened on the firewall for the FTP server to function properly?
You must open TCP ports 20 and 21 for the FTP server to function properly.
serve both files and printers to users
The lftp command can be used on a client to test FTP server connections.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.

45. What two commands are special for dealing with user login events?
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
kickstart installations to work
The testparm command allows you to check for syntax errors in the /etc/samba/smb.conf file.
The lastlog and faillog commands are used to view user login-related events?

46. What is the name of the section used to run scripts after a kickstart installation?
By defining a %post section - you can run scripts after a kickstart installation is complete.
The nfsstat command can be used to view NFS statistics.
mkfs.ext4
export one or all resources

47. Editing the /etc/xinetd.d/tftp file and enabling the service are the same as running the chkconfig tftp on command. Both of these actions...
The testparm command allows you to check for syntax errors in the /etc/samba/smb.conf file.
have the same effect
The virsh command is used to manage virtual guests.
Kickstart supports both basic and advanced partitioning (RAID/LVM).

48. What are the five required directories when building RPMS?
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
The -t nfs option is used with the mount command to mount NFS resources.
Enforcing during installation
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.

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

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50. A service needs to have _______________ to be able to use it.
The lftp command can be used on a client to test FTP server connections.
SELinux provides enhanced granular security for the Linux operating system.
support for TCP Wrappers
Using the host option in the dhcpd.conf file allows you to reserve a client IP address based on its MAC address.