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. SSH does...
support TCP Wrappers
Version 2 is the latest and most secure version of SSH.
Use the resize2fs command to grow a file system.
The dig - host - and ping commands can be used to test DNS server functionality.


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

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4. What command can you use to query Boolean values?
The yum and rpm commands are used for package management.
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.
getsebool
browseable option


5. What does the partprobe command do?
A user's home directory is created under the /home directory.
Use the resize2fs command to grow a file system.
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
used for kickstart and/or network installs


6. To create a RAID or LVM partition using kickstart
Kickstart supports both basic and advanced partitioning (RAID/LVM).
The -t nfs option is used with the mount command to mount NFS resources.
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.
semanage boolean -l


7. A service needs to have _______________ to be able to use it.
support for TCP Wrappers
halts the system
The /var/log/audit/audit.log file contains all policy violations.
The smbstatus command shows you currently mounted Samba resources.


8. Can you name the two commands that can be used to view the free space on the system?
A virtual host is a way of hosting multiple sites using a single IP address.
semanage boolean -l
The du and df commands are used to view available space on the system.
schedule one-time-only jobs


9. What three commands can you use to help verify that the DNS server is functioning properly?
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.
The dig - host - and ping commands can be used to test DNS server functionality.
chcon
The /etc/fstab file.


10. How can you change the security context of a directory to work with Apache?
generates errors under Red Hat Enterprise Linux 6
Using the chcon command - you can change the context of a file to work with Apache.
service dhcpd configtest
SELinux provides enhanced granular security for the Linux operating system.


11. What command can you use to validate the syntax of the Apache config file?
service httpd configtest
A web proxy can provide multiple benefits - including security - web page caching for faster load times - and load balancing.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.
support TCP Wrappers


12. What is the format of the /etc/shadow file?
The du and df commands are used to view available space on the system.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
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 five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.


13. Place all files you want added to a _______________ during creation.

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14. If you want a specific action to take place when user01 logs in to the system - which file would you edit?
You add your action to the end of the /home/user01/.bashrc 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.
Use the resize2fs command to grow a file system.
By using centralized authentication - you don't need to re-create or maintain multiple accounts across every system in your organization.


15. What command can you use to test connectivity to another host?
Kickstart supports both basic and advanced partitioning (RAID/LVM).
chkconfig sshd off
Version 2 is the latest and most secure version of SSH.
The ping command can be used to verify connectivity to another host.


16. What command can you use to manage system services?
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.
atq
The yum and rpm commands are used for package management.
The service command is used to start - stop - and manage system services.


17. The old SysInit scripts have been replaced in Red Hat Enterprise Linux 6 for what new boot utility?
The virsh command is used to manage virtual guests.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.
A large warning message appears indicating that the key doesn't match the host you are connecting to. You have to remove the key/host pair from the known_hosts file to proceed.
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.


18. The virt-install package allows you to manage virtual machines _____________. The virt-manager package allows you to manage virtual machines via a GUI interface.
via the command line
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.
The /etc/fstab file.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.


19. What command is used to change the mail server from Sendmail to Postfix (useful only if you have both installed)?
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
used for kickstart and/or network installs
alternatives --config mta
The /etc/fstab file.


20. What option at the GRUB boot menu can you use to append something to a kernel?
The /etc/hosts file is a local lookup file used to map IP addresses to hostnames if a DNS server isn't available.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
Network installations can be performed using the HTTP - FTP - and NFS protocols.


21. What three components are needed to fully automate a kickstart installation?
SELinux provides enhanced granular security for the Linux operating system.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.
entering rescue mode and repairing the problem.
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.


22. If a package is built on an RHEL6 system and deployed to a custom RHEL5 repository - are RHEL5 systems able to use it?
chcon
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
No. Red Hat Enterprise Linux 6 uses a different key to sign its packages.
used for kickstart and/or network installs


23. What command do you use to report information on quota usage?
getfacl
repquota
For Apache to run a secure site - the mod_ssl package is required to be installed.
The lftp command can be used on a client to test FTP server connections.


24. Runlevel 0 ___________. Runlevel 6 reboots the system.
halts the system
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.
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.
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.


25. FTP is one of three protocols ______________. The other two protocols are NFS and HTTP.
Apache uses port 80 for HTTP and port 443 for HTTPS.
used for kickstart and/or network installs
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 file that stores usernames and their encrypted passwords is erased and replaced with a new file.


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

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27. How can you verify the status of the SSH service after the system has booted?
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
cat /proc/mdstat
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
service sshd statuts


28. What are the three modes in which the rpm command can operate?
The rpm command can operate in install - query - or verify modes.
support for TCP Wrappers
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
A virtual host is a way of hosting multiple sites using a single IP address.


29. 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.
You must open TCP ports 20 and 21 for the FTP server to function properly.
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
have the same effect


30. How would you disable SELinux protection for NFS - allowing shares to be read/write?
The DHCP server listens on port 67 by default.
lvdisplay
The two main config files are master.cf and main.cf.
setsebool -P nfs_export_all_rw=1


31. What command can be used to view the queue for at service jobs?
atq
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.
A user's home directory is created under the /home directory.
service named configtest


32. What is the superblock 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 superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.
The SMTP service runs on TCP port 110.
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.


33. 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.
used for kickstart and/or network installs
browseable option
defining a %pre section although it is rarely used
Enforcing during installation


34. What is a gateway used for on a network?
Typing the mail or mutt command allows you to read mail from the command line.
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 /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
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.


35. Can you name three utilities that can be used for network or DNS client troubleshooting?
This command reboots virtual guest Client04.
Use the setgid flag to create the appropriate permissions (chmod 2770).
setsebool -P nfs_export_all_rw=1
The three utilities are: route - ping - and nslookup.


36. What is SSH used for?
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 NFS service uses TCP port 2049 by default.
lvdisplay
SSH is used for secure remote management of Linux systems.


37. How can virtual hosts be used?
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.
kickstart installations to work
via the command line
The htpasswd command can be used to password-protect a web page.


38. What is the main config file for the DHCP service?
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.
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 /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
You can use the authconfig-tui command or the authconfig command.


39. What command can you use to test the config files before starting the DNS service?
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.
By using centralized authentication - you don't need to re-create or maintain multiple accounts across every system in your organization.
service named configtest
By default - Squid runs on port 3128.


40. What is the biggest benefit to using LVM over basic partitions?
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.
SELinux Booleans provide restrictions to different aspects of a service.
The NFS service uses TCP port 2049 by default.
The TFTP server uses UDP port 69.


41. What is the name of the package used to install an FTP?
The anonymous_enable=YES option in the main config file allows anonymous uploads.
The vsftpd package is used to install an FTP server.
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.
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


42. What port does the SMTP service run on?
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
By default - Squid runs on port 3128.
The SMTP service runs on TCP port 110.
The testparm command allows you to check for syntax errors in the /etc/samba/smb.conf file.


43. What are the three different types of RAID described in this chapter?
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
A web proxy can provide multiple benefits - including security - web page caching for faster load times - and load balancing.
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.


44. What is the default port that Squid runs on?
By default - Squid runs on port 3128.
Enforcing during installation
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.
you have access to the correct packages or repositories.


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

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46. The portmap service was replaced by the ______________ in Red Hat Enterprise Linux 6.
The virsh command is used to manage virtual guests.
rpcbind service
amount of RAM
getsebool -a | grep http


47. The at command is used to ____________. The cron service handles reoccurring system jobs.
The file system where quotas will be implemented must be mounted with the usrquota and grpquota options before quotas will work properly.
schedule one-time-only jobs
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 /etc/exports file needs to contain any directory that you want to export - including which options you'd like to use as well.


48. What client-side command can you use to test your FTP server connection?
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 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.
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 lftp command can be used on a client to test FTP server connections.


49. What command (and options) can be used to create a user named George with the description "Jr Admin"?
useradd -c "Jr Admin" George
alternatives --config mta
browseable option
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.


50. What command can you use to view NFS statistics?
The nfsstat command can be used to view NFS statistics.
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.
Enforcing during installation
service sshd statuts