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 does the following firewall rule accomplish: iptables -I INPUT 5 -p tcp -m tcp --dport 80 -j ACCEPT?
kickstart installations to work
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 user_list file can be used to limit which users have access to the FTP server.
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.


2. What command can you use to check the config file of the DHCP server?
service dhcpd configtest
SELinux provides enhanced granular security for the Linux operating system.
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
generates errors under Red Hat Enterprise Linux 6


3. What command can you use to create a new SSL certificate?
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
support TCP Wrappers
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
service httpd configtest


4. What does virsh reboot Client04 do?
Using the chcon command - you can change the context of a file to work with Apache.
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.
This command reboots virtual guest Client04.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.


5. What port must be opened on the firewall for DNS?
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.
atq
The DHCP server listens on port 67 by default.
DNS uses port 53.


6. What command can you use to validate the syntax of the Apache config file?
service httpd configtest
The htpasswd command can be used to password-protect a web page.
SELinux provides enhanced granular security for the Linux operating system.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.


7. What does it mean if you ping a host and you receive the response Destination Unreachable?
The htpasswd command can be used to password-protect a web page.
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
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.
By using centralized authentication - you don't need to re-create or maintain multiple accounts across every system in your organization.


8. What command do you use to report information on quota usage?
repquota
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 service command is used to start - stop - and manage system services.
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.


9. To create a RAID or LVM partition using kickstart
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.
Kickstart supports both basic and advanced partitioning (RAID/LVM).
The tcpdump command is used to monitor network connections on different interfaces.
getfacl


10. What command can you use to view system processes and their CPU usage?
setsebool -P nfs_export_all_rw=1
getsebool -a | grep http
Use the ps command to view processes and their CPU usage.
support TCP Wrappers


11. What critical step must you take after updating the kernel to a newer version?
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.
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.


12. 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.
service dhcpd configtest
semanage boolean -l
The two main config files are master.cf and main.cf.


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

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14. What two commands are special for dealing with user login events?
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
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.
After the ntpd service is stopped - you can use the ntpdate <server> command to update/sync the time.
The lastlog and faillog commands are used to view user login-related events?


15. What does the rdnc-confgen command do?
The rdnc-confgen command generates an rndc.conf file for the rndc utility.
The service command is used to start - stop - and manage system services.
Kickstart supports both basic and advanced partitioning (RAID/LVM).
via the command line


16. The default SMTP service has been changed from _________ to Postfix in Red Hat Enterprise Linux 6.
Sendmail
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
The /var/log/audit/audit.log file contains all policy violations.
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


17. 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.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
A web proxy can provide multiple benefits - including security - web page caching for faster load times - and load balancing.
Use the ps command to view processes and their CPU usage.


18. Which version of SSH should you use?
halts the system
Version 2 is the latest and most secure version of SSH.
The NFS service uses TCP port 2049 by default.
The xinetd daemon is used to control and/or run multiple system services. One example is a TFTP server.


19. What does S12rsyslog in the /etc/rc.d/rc2.d directory mean?
getsebool
Use the yum groupinstall command to install multiple packages in a single group at once.
The vsftpd package is used to install an FTP server.
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.


20. How would you view all Boolean options for the HTTP service?
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.
getsebool -a | grep http
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.
Using the chcon command - you can change the context of a file to work with Apache.


21. Samba servers can...
serve both files and printers to users
The htpasswd command can be used to password-protect a web page.
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.
ifconfig


22. How would you install a group of packages all at a single time?
Use the yum groupinstall command to install multiple packages in a single group at once.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.
The smbpasswd command is used to create Samba users.
The print option is used with both the fdisk and parted commands to display the current partition tables.


23. Which remote management service is installed by default?Can you name the port that it uses?
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.
service sshd statuts
kickstart installations to work
halts the system


24. What is the difference between the update (-U) and install (-i) options when using rpm to update the kernel?
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
setsebool -P nfs_export_all_rw=1
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 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. What file is used to maintain custom parameters for the kernel during system boot?
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.
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
Enforcing during installation
SSH is used for secure remote management of Linux systems.


26. The old SysInit scripts have been replaced in Red Hat Enterprise Linux 6 for what new boot utility?
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.
The smbstatus command shows you currently mounted Samba resources.
You must open TCP ports 20 and 21 for the FTP server to function properly.


27. What two ports should be opened on the firewall for the FTP server to function properly?
This chapter described tdbsm and smbpasswd back-end authentication.
browseable option
You must open TCP ports 20 and 21 for the FTP server to function properly.
The two main config files are master.cf and main.cf.


28. What option can you change in the rsyslog config file to accept remote logs (acting as a centralized logging server)?
The NFS service uses TCP port 2049 by default.
run on any port you'd like (provided that port is available)
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.


29. What command can you use to test connectivity to another host?
The ping command can be used to verify connectivity to another host.
Typing the mail or mutt command allows you to read mail from the command line.
The TFTP server uses UDP port 69.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.


30. What port does the Apache web server run on - What about HTTPS?
You can use the sudo command to run a command with elevated privileges provided you have the rights in the /etc/sudoers file.
Apache uses port 80 for HTTP and port 443 for HTTPS.
The dig - host - and ping commands can be used to test DNS server functionality.
getfacl


31. What command can you use to query Boolean values?
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.
You add your action to the end of the /home/user01/.bashrc file.
getsebool


32. SSH does...
service httpd configtest
run on any port you'd like (provided that port is available)
support TCP Wrappers
schedule one-time-only jobs


33. Can you name three utilities that can be used for network or DNS client troubleshooting?
via the command line
A user's home directory is created under the /home directory.
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.
The three utilities are: route - ping - and nslookup.


34. To grow a file system
You add your action to the end of the /home/user01/.bashrc file.
Use the resize2fs command to grow a file system.
By defining a %post section - you can run scripts after a kickstart installation is complete.
An A record translates translated hostnames to IP addresses - and a PTR record works the other way around.


35. What is the format of the /etc/shadow file?
The mount command lists all currently mounted file systems.
For Apache to run a secure site - the mod_ssl package is required to be installed.
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
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.


36. 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...
have the same effect
Using the host option in the dhcpd.conf file allows you to reserve a client IP address based on its MAC address.
The /var/lib/nfs/etab file is used to keep track of currently exported resources.
halts the system


37. What happens if a host changes its IP address and the keys don't match?

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38. What command do you use to change the permissions on a file or directory - To change ownership?
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 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.
Using the chcon command - you can change the context of a file to work with Apache.
The smbstatus command shows you currently mounted Samba resources.


39. 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.
The /etc/hosts file is a local lookup file used to map IP addresses to hostnames if a DNS server isn't available.
Enforcing during installation
This command reboots virtual guest Client04.


40. You must dictate the ____________ you want allocated to your virtual machine when you create it.
rpcbind service
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.
amount of RAM
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.


41. How can you check the currently mounted file systems?
The mount command lists all currently mounted file systems.
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 NFS service uses TCP port 2049 by default.
The virsh command is used to manage virtual guests.


42. What is a swap? Is it created as a partition or device file?
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
service dhcpd configtest
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.
The three utilities are: route - ping - and nslookup.


43. The INPUT chain being used is the default under Red Hat Enterprise Linux 5. This rule...
generates errors under Red Hat Enterprise Linux 6
setsebool -P nfs_export_all_rw=1
The virsh command is used to manage virtual guests.
Use the ps command to view processes and their CPU usage.


44. What option needs to be used with the mount command to mount an NFS resource?
By using centralized authentication - you don't need to re-create or maintain multiple accounts across every system in your organization.
The -t nfs option is used with the mount command to mount NFS resources.
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
getsebool


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

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46. Where are Yum repository config files located?
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
Apache uses port 80 for HTTP and port 443 for HTTPS.
Typing the mail or mutt command allows you to read mail from the command line.
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.


47. What does ifconfig 172.168.1.100 netmask 255.255.255.0 eth1 do?
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.
This chapter described tdbsm and smbpasswd back-end authentication.
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.
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.


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

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

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50. What port does NFS use by default?
The NFS service uses TCP port 2049 by default.
chcon
Use the resize2fs command to grow a file system.
createrepo