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 three commands can you use to help verify that the DNS server is functioning properly?
The dig - host - and ping commands can be used to test DNS server functionality.
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.
The file system where quotas will be implemented must be mounted with the usrquota and grpquota options before quotas will work properly.
Use the resize2fs command to grow a file system.


2. What command can you use to create a file system?
mkfs.ext4
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
You can use the sudo command to run a command with elevated privileges provided you have the rights in the /etc/sudoers file.
Use the chkconfig command to enable or disable services during the boot process. The on option enables the service and off disables it.


3. What command can be used to easily list all the options in the FTP main config file?
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.
generates errors under Red Hat Enterprise Linux 6
Using the chcon command - you can change the context of a file to work with Apache.
chkconfig sshd off


4. How can you change the security context of a directory to work with Apache?
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.
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.
Using the chcon command - you can change the context of a file to work with Apache.
Use the setgid flag to create the appropriate permissions (chmod 2770).


5. What is the default port that Squid runs on?
The file system where ACLs will be implemented must be mounted with the acl option before ACLs will work properly.
By default - Squid runs on port 3128.
The DHCP server listens on port 67 by default.
By defining a %post section - you can run scripts after a kickstart installation is complete.


6. Through its main config file - SSH can be configured to...

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7. What critical step must you take after updating the kernel to a newer version?
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.
setsebool -P nfs_export_all_rw=1
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.
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.


8. What command can you use to query information from the kernel about RAID arrays?
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
cat /proc/mdstat
The three utilities are: route - ping - and nslookup.
The rpm command can operate in install - query - or verify modes.


9. What are the five required directories when building RPMS?
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
This command reboots virtual guest Client04.
mkfs.ext4
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.


10. What file needs to be edited so that the system will mount a file system at boot time?
The -t nfs option is used with the mount command to mount NFS resources.
ifconfig
The /etc/exports file needs to contain any directory that you want to export - including which options you'd like to use as well.
The /etc/fstab file.


11. What three protocols can you use to perform network installations?
The three utilities are: route - ping - and nslookup.
Network installations can be performed using the HTTP - FTP - and NFS protocols.
Use the setgid flag to create the appropriate permissions (chmod 2770).
The two main config files are master.cf and main.cf.


12. To export directories as resources - what file needs to be edited?

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

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14. What option needs to be used with the mount command to mount an NFS resource?
Physical volumes - volume groups - and logical volumes.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
The -t nfs option is used with the mount command to mount NFS resources.


15. What three components are needed to fully automate a kickstart installation?
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.
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.
halts the system
cat /proc/mdstat


16. What command is used to create a user for Samba?
The print option is used with both the fdisk and parted commands to display the current partition tables.
The smbpasswd command is used to create Samba users.
A virtual host is a way of hosting multiple sites using a single IP address.
createrepo


17. What is the biggest benefit to using LVM over basic partitions?
Physical volumes - volume groups - and logical volumes.
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 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 /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.


18. What is the main config file for the DHCP service?
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.
ifconfig
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.
The /etc/dhcp/dhcpd.conf file is the main config file for the DHCP service.


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

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20. How would you disable SELinux protection for NFS - allowing shares to be read/write?
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.
The VNC package for Red Hat Enterprise Linux 6 is tiger-vnc.
setsebool -P nfs_export_all_rw=1
By defining a %post section - you can run scripts after a kickstart installation is complete.


21. The INPUT chain being used is the default under Red Hat Enterprise Linux 5. This rule...
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.
generates errors under Red Hat Enterprise Linux 6
The /var/lib/nfs/etab file is used to keep track of currently exported resources.
serve both files and printers to users


22. What is a swap? Is it created as a partition or device file?
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.
Use the ps command to view processes and their CPU usage.
getsebool -a | grep http
An ext3 file system has journaling built in to it - whereas the ext2 file system doesn't.


23. A slave DNS server provides...
Version 2 is the latest and most secure version of SSH.
export one or all resources
load balancing and redundancy benefits
Typing the mail or mutt command allows you to read mail from the command line.


24. 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.
The print option is used with both the fdisk and parted commands to display the current partition tables.
You must open TCP ports 20 and 21 for the FTP server to function properly.
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.


25. Can you put your /boot partition on a RAID 5 array?
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.
The superblock is a structure that contains metadata of the file system. If this becomes corrupt - you are in trouble.
repquota
The /var/lib/nfs/etab file is used to keep track of currently exported resources.


26. The ____________ is available for each share.
The tcpdump command is used to monitor network connections on different interfaces.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.
browseable option
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).


27. What is a virtual host?
A virtual host is a way of hosting multiple sites using a single IP address.
The SMTP service runs on TCP port 110.
A user's home directory is created under the /home directory.
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.


28. What port does the rndc utility listen on by default?
The /var/lib/nfs/etab file is used to keep track of currently exported resources.
Apache uses port 80 for HTTP and port 443 for HTTPS.
By default - the rndc utility listens on port 953.
Network installations can be performed using the HTTP - FTP - and NFS protocols.


29. What command is used to change the mail server from Sendmail to Postfix (useful only if you have both installed)?
The /etc/sysctl.conf file maintains a list of custom kernel parameters that should be applied during system boot.
The file that stores usernames and their encrypted passwords is erased and replaced with a new file.
alternatives --config mta
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.


30. What command and option do you use to view the description of Boolean values?
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.
semanage boolean -l
used for kickstart and/or network installs
Use the /usr/share/doc/dovecot-1.0.7/examples/mkcert.sh command after editing the /etc/pki/dovecot/dovecot-openssl.cnf file.


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

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32. The at command is used to ____________. The cron service handles reoccurring system jobs.
Upstart. The Upstart utility is now used in the boot process for Red Hat Enterprise Linux 6.
The five directories are BUILD - RPMS - SOURCES - SPECS - and SRPMS.
schedule one-time-only jobs
Typing the mail or mutt command allows you to read mail from the command line.


33. A service needs to have _______________ to be able to use it.
The du and df commands are used to view available space on the system.
getfacl
Enforcing during installation
support for TCP Wrappers


34. How can you list all services on the system to tell whether they will boot during startup?
By combining a TFTP server - PXE boot - and DHCP server - you can fully automate the kickstart installation process.
The yum and rpm commands are used for package management.
chkconfig—list
rpmbuild


35. What is the name of the package used to install an FTP?
The format of the /etc/shadow file is <username>:<encrypted password>:<last passwd change>:<min>:<max>:<warn>:<inactive>:<expires>:<not used>.
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.
The vsftpd package is used to install an FTP server.
chkconfig—list


36. What directory is used to represent the virtual file system created by the kernel?
getsebool -a | grep http
alternatives --config mta
The /proc directory. The /proc/sys directory is the place where you actually tune kernel parameters.
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.


37. What client-side command can you use to test your FTP server connection?
createrepo
Kickstart supports both basic and advanced partitioning (RAID/LVM).
The lftp command can be used on a client to test FTP server connections.
rpcbind service


38. 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.
getsebool -a | grep http
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.
After you connect to a hypervisor - you can use virsh list —all to list all virtual guests.


39. What command can you use to test connectivity to another host?
VNC is used to control a remote desktop session.
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 ping command can be used to verify connectivity to another host.
support TCP Wrappers


40. What command can you use to test the config files before starting the DNS service?
The print option is used with both the fdisk and parted commands to display the current partition tables.
service named configtest
Uncomment the following line in the /etc/rsyslog.conf file: #$ModLoad imudp.so #$UDPServerRun 514
The NFS service uses TCP port 2049 by default.


41. How can you verify the status of the SSH service after the system has booted?
chkconfig sshd off
service sshd statuts
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.
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


42. What command can you use to check the config file of the DHCP server?
service dhcpd configtest
Network installations can be performed using the HTTP - FTP - and NFS protocols.
entering rescue mode and repairing the problem.
No. Red Hat Enterprise Linux 6 uses a different key to sign its packages.


43. What command and options can you use to update the time?
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
After the ntpd service is stopped - you can use the ntpdate <server> command to update/sync the time.
The -t nfs option is used with the mount command to mount NFS resources.
VNC is used to control a remote desktop session.


44. There are four types of DNS servers. Name them.
The /var/liv/dhcpd/dhcpd.leases file contains all clients IP address currently in use.
The four types of DNS servers are master - slave - caching-only - and forwarding.
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.
Apache uses port 80 for HTTP and port 443 for HTTPS.


45. What are SELinux Booleans?
service dhcpd configtest
The nfsstat command can be used to view NFS statistics.
SELinux Booleans provide restrictions to different aspects of a service.
The last rule is always an implicit deny statement rejecting anything that wasn't matched by previous rules.


46. What port must be opened on the firewall for DNS?
Apache uses port 80 for HTTP and port 443 for HTTPS.
RAID 0 (Striping) - RAID 1 (Mirror) - and RAID 5 (Striping with parity).
DNS uses port 53.
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


47. What is the point of using SELinux?
semanage boolean -l
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.
chkconfig—list
SELinux provides enhanced granular security for the Linux operating system.


48. What does the partprobe command do?
The partprobe command forces the kernel to reread the partition table. You should always call it after making any changes to your system partitions.
amount of RAM
kickstart installations to work
The grep -v ^# /etc/vsftpd/vsftpd.conf command shows you all the options currently being used with the FTP server.


49. What command can you use to manage system services?
repquota
The service command is used to start - stop - and manage system services.
Dovecot supports the POP3 - POP3S - IMAP - and IMAPS protocols.
The tcpdump command is used to monitor network connections on different interfaces.


50. What option at the GRUB boot menu can you use to append something to a kernel?
The gateway is incorrectly set - and the subnet of the host you are trying to reach is inaccessible.
The nfsstat command can be used to view NFS statistics.
The rndc utility provides a method for managing the DNS server remotely and securely.
By entering the GRUB boot menu - you can choose the a option to append something to the kernel command-line options.