102-500無料試験学習ガイド！（更新された236問あります) [Q57-Q82]

102-500無料試験学習ガイド！（更新された236問あります)

102-500問題集にはLPIC Level1認証済み試験問題と解答

質問 # 57
To prevent a specific user from scheduling tasks with at, what should the administrator do?

• A. Add the specific user to /etc/at.allow file.
• B. Add the specific user to nojobs group.
• C. Add the specific user to /etc/at.deny file.
• D. Add the specific user to [deny] section in the /etc/atd.conf file.
• E. Run the following: atd --deny [user].

正解：C

解説：
The /etc/at.deny file is a file that contains a list of users who are not allowed to use the at command to schedule jobs. If the file exists, any user who is not in the /etc/at.allow file and is in the /etc/at.deny file will be denied access to the at command. To prevent a specific user from scheduling tasks with at, the administrator can simply add the user's name to the /etc/at.deny file. For example, to prevent the user bob from using the at command, the administrator can use the following command:
echo "bob" | sudo tee -a /etc/at.deny
The other options are not correct. The /etc/at.allow file is a file that contains a list of users who are allowed to use the at command. Adding a user to this file will not prevent them from scheduling tasks with at. The /etc/atd.conf file is a configuration file for the at daemon, which does not have a [deny] section. Adding a user to this file will not affect their access to the at command. The nojobs group is not a predefined group in Linux, and adding a user to this group will not prevent them from scheduling tasks with at. The atd command does not have a --deny option, and running this command will not prevent a user from scheduling tasks with at. Reference:
at Command in Linux with Examples - GeeksforGeeks
How to Use the Linux at Command {9 Examples} - phoenixNAP
at(1) - Linux man page

質問 # 58
Which of the following is a valid IPv6 address?

• A. 2001::db8:4581::1
• B. 2001:db8:3241::1
• C. 2001.db8.819f..1
• D. 2001%db8%9990%%1
• E. 2001:db8:0g41::1

正解：B

解説：
A valid IPv6 address is represented as a set of 16-bit hexadecimals separated by colons. The address is divided into eight groups, and each 16-bit group is represented by four hexadecimal numbers. A valid IPv6 address is in the form "x1:x2:x3:x4:x5:x6:x7:x8" where each xi is a hexadecimal string which may contain digits, lower-case English letter ('a' to 'f') and upper-case English letters ('A' to 'F'). Leading zeros are allowed in xi. The longest sequence of consecutive all-zero fields is replaced with two colons (::).1 Option A is the only one that follows these rules. Option B has two consecutive colons twice, which is not allowed. Option C has an invalid hexadecimal character 'g'. Option D uses percentage signs instead of colons, which is not a valid separator. Option E uses dots instead of colons, and has two consecutive dots, which are both invalid.

質問 # 59
What is true about the Hop Limit field in the IPv6 header?

• A. The field is not changed during the transport of a package.
• B. The field is transmitted within a hop-by-hop extension header.
• C. Each router forwarding the packet decreases the field's value.
• D. Each router forwarding the packet increases the field's value.
• E. For multicast packages, the field's value is always 1.

正解：C

質問 # 60
Which of the following are commonly used Mail Transfer Agent (MTA) applications? (Choose THREE correct answers.)

• A. Procmail
• B. Postfix
• C. Exim
• D. Sendmail
• E. SMTPd

正解：B、C、D

解説：
Postfix, Sendmail, and Exim are three of the most commonly used Mail Transfer Agent (MTA) applications on Linux systems. An MTA is a software that transfers and routes electronic mail messages from one computer to another using the Simple Mail Transfer Protocol (SMTP). An MTA receives messages from another MTA or from a Mail User Agent (MUA), which is a computer application that end users use to access or send emails. An MTA can also query the MX records of the recipient's domain to find the destination mail server and forward the message accordingly. An MTA can also perform other functions such as filtering, encryption, authentication, and bounce handling.
Postfix is a cross-platform, popular MTA that was designed and developed by Wietse Zweitze Venema for his mail server while working at the IBM research department. It was primarily developed as an alternative to well-known and popular Sendmail MTA. Postfix runs on Linux, Mac OSX, Solaris, and several other Unix-like operating systems. It borrows a lot of Sendmail properties on the outside, but it has a totally and comprehensively distinct internal operation. Additionally, it bids to be fast in performance with easy configurations and secure operation mechanism1.
Sendmail, now known as Proofpoint (after Proofpoint, Inc acquired Sendmail, Inc), is by far the most popular and one of the oldest MTA on the Linux server platform. Sendmail has a lot of limitations though, in comparison to modern MTAs. Because of its complicated configuration steps and demands, and weak security mechanisms, many new MTAs have come up as alternatives to Sendmail, but importantly, it offers everything to do with mail on a network1.
Exim is a free MTA developed for Unix-like operating systems such as Linux, Mac OSX, Solaris, and many more. Exim offers a great level of flexibility in routing mail on a network, with outstanding mechanisms and facilities for incoming mail monitoring. Its notable features include among others: no support for POP and IMAP protocols, supports protocols such as RFC 2821 SMTP and RFC 2033 LMTP email message transport, configurations include access control lists, content scanning, encryption, routing controls among others1.
Procmail is not an MTA, but a mail processing utility that can be used to filter, sort, and deliver incoming mail. It can be invoked by an MTA or run as a standalone program. Procmail can process mail based on various criteria such as sender, subject, header, body, size, date, and more. It can also execute external programs, forward mail to another address, or write mail to a file.
SMTPd is not an MTA, but a generic name for a daemon (a background process) that implements the SMTP protocol. A daemon is a program that runs continuously and performs certain tasks at predefined times or in response to certain events. An SMTP daemon listens for incoming SMTP connections from other MTAs or MUAs and handles the mail transfer accordingly. SMTPd can also refer to a specific SMTP daemon that is part of the OpenSMTPD project, which is a free implementation of the SMTP protocol for Unix systems. Reference:
7 Best Mail Transfer Agents (MTA's) for Linux
Mail Transfer Agent (MTA) Explained | Mailtrap Blog
What is a Message Transfer Agent (MTA)? - Definition from Techopedia
Mail Transfer Agent (MTA) - Glossary of Email Terms | Mailgun
[Procmail - Wikipedia]
[SMTP daemon - Wikipedia]

質問 # 61
What is true regarding the command sendmail?

• A. With any MTA, the sendmail command must be run periodically by the cron daemon.
• B. The sendmail command prints the MTAs queue history of which mails have been sent successfully.
• C. It is only available when the sendmail MTA is installed.
• D. All MTAs, including Postfix and Exim, provide a sendmail command.

正解：D

質問 # 62
Which command is used to set the hostname of the local system? (Specify ONLY the command without any path or parameters.)

正解：

解説：
hostname

質問 # 63
Given the following routing table:

How would an outgoing packet to the destination 192.168.2.150 be handled?

• A. It would be passed to the default router 255.255.255.0 on eth0.
• B. It would be passed to the default router 192.168.178.1 on wlan0.
• C. It would be passed to the router 192.168.1.1 on eth0.
• D. It would be directly transmitted on the device wlan0.
• E. It would be directly transmitted on the device eth0.

正解：C

質問 # 64
On a Linux system with shadow passwords enabled, which file in the file system contains the password hashes of all local users? (Specify the full name of the file, including path.)

正解：

解説：
/etc/shadow
Explanation:
On a Linux system with shadow passwords enabled, the file that contains the password hashes of all local users is /etc/shadow. This file is a replacement for the password field in /etc/passwd, which is a world-readable file that contains basic information about users. The /etc/shadow file is not readable by regular users, and it stores the encrypted passwords (or hashes) of each user, along with other information such as password expiration dates, minimum and maximum password ages, and password warning periods. The /etc/shadow file has nine colon-delimited fields for each user:
* Username: The name used when the user logs into the system.
* Password: The encrypted password of the user, or a special character that indicates the password status.
For example, an asterisk (*) means the account is locked, and an exclamation mark (!) means the password is expired.
* Last Password Change: The date of the last password change, expressed as the number of days since January 1, 1970.
* Minimum Password Age: The minimum number of days required between password changes. A zero means the password can be changed anytime.
* Maximum Password Age: The maximum number of days the password is valid. After this number of days, the password must be changed. A zero means the password never expires.
* Password Warning Period: The number of days before the password expires that the user will be warned. A zero means no warning is given.
* Password Inactivity Period: The number of days after the password expires that the account will be disabled. A negative value means the account is never disabled.
* Account Expiration Date: The date when the account will be disabled, expressed as the number of days since January 1, 1970. A zero means the account never expires.
* Reserved Field: A field for future use.
The /etc/shadow file can be modified by using the commands passwd and chage, which are used to change the password and the password aging information of a user, respectively. The /etc/shadow file should not be edited directly, but always through the tools provided by the distribution. For more details, see the shadow manual page.
References:
* LPIC-1 Exam 102 Objectives, Topic 110: Security, Subtopic 110.2: Use sudo to manage access to the root account, Weight: 2, Key Knowledge Areas: Configure sudo and sudoers. Use sudo to execute commands as another user.
* LPIC-1 Exam 102 Learning Materials, Topic 110: Security, Subtopic 110.2: Use sudo to manage access to the root account, Section 110.2.1: sudo and sudoers, Page 3-5.

質問 # 65
How do shadow passwords improve the password security in comparison to standard no-shadow password?

• A. Shadow passwords are stored in plain text and can be checked for weak passwords.
• B. Regular users do not have access to the password hashes of shadow passwords.
• C. The system's host key is used to encrypt all shadow passwords.
• D. Every shadow password is valid for 45 days and must be changed afterwards.
• E. Shadow passwords are always combined with a public key that has to match the user's private key.

正解：B

質問 # 66
Which option in the /etc/ntp.conf file specifies an external NTP source to be queried for time information? (Specify ONLY the option without any values or parameters.)

正解：

解説：
server
Explanation:
The server option is used to configure a persistent association with a remote server or peer. It takes an argument that is either a host name or a numeric IP address of the NTP server. The ntpd daemon will periodically send NTP packets to the specified server and adjust the local clock according to the received responses. Multiple server options can be used to specify more than one NTP source. For example, the following lines in the /etc/ntp.conf file configure four external NTP sources:
server 0.asia.pool.ntp.org
server 0.oceania.pool.ntp.org
server 0.europe.pool.ntp.org
server 0.north-america.pool.ntp.org
Reference:
https://docs.ntpsec.org/latest/ntp_conf.html
https://vceguide.com/which-option-in-the-etc-ntp-conf-file-specifies-an-external-ntp-source-to-be-queried-for-time-information-2/
https://vceguide.com/which-option-in-the-etcntp-conf-file-specifies-an-external-ntp-source-to-be-queried-for-time-information/

質問 # 67
Which of the following commands will help identify a broken router between the local and the remote machine?

• A. nslookup
• B. netstat
• C. ps
• D. ifconfig
• E. traceroute

正解：E

解説：
The traceroute command will help identify a broken router between the local and the remote machine. The traceroute command sends a series of packets with increasing time-to-live (TTL) values to a destination and displays the routers that the packets pass through along the way. If a router is broken or unreachable, the traceroute command will show a * symbol or a timeout message. The traceroute command is part of the topic
109.1: Fundamentals of internet protocols, which is one of the objectives of the LPI Linux Administrator - 102 exam12. References: 1: https://learning.lpi.org/en/learning-materials/102-500/ 2:
https://www.lpi.org/our-certifications/exam-102-objectives/

質問 # 68
Which standardized TCP port is used by HTTPS services?

• A. 0
• B. 1
• C. 2
• D. 3
• E. 4

正解：E

質問 # 69
Which of the following are tasks handled by a display manager like XDM or KDM? (Choose TWO correct answers.)

• A. Create an X11 configuration file for the current graphic devices and monitors.
• B. Lock the screen when the user was inactive for a configurable amount of time.
• C. Handle the login of a user.
• D. Start and prepare the desktop environment for the user.
• E. Configure additional devices like new monitors or projectors when they are attached.

正解：C、D

解説：
The tasks that are handled by a display manager like XDM or KDM are to start and prepare the desktop environment for the user and to handle the login of a user. A display manager is a software component that manages the graphical user interface of an operating system. It provides a login screen where the user can enter their credentials and choose their preferred desktop environment or window manager. After the user is authenticated, the display manager launches the selected desktop environment or window manager and sets up the graphical session. The display manager also handles the logout, shutdown, and reboot of the system.
The other options are incorrect because they are not tasks handled by a display manager:
* B. Configure additional devices like new monitors or projectors when they are attached. This task is handled by the X server, which is the core component of the X Window System. The X server is responsible for communicating with the hardware devices, such as the keyboard, mouse, monitor, and graphics card. The X server can detect and configure new devices dynamically using tools like xrandr or xorg.conf.
* D. Lock the screen when the user was inactive for a configurable amount of time. This task is handled by the screensaver program, which is a utility that runs in the background and activates when the user is idle for a certain period of time. The screensaver can display various animations or images on the screen, or it can blank the screen entirely. The screensaver can also lock the screen and require the user to enter their password to resume the session. The screensaver can be configured by the user using tools like xscreensaver or gnome-screensaver.
* E. Create an X11 configuration file for the current graphic devices and monitors. This task is handled by the X server, which is the core component of the X Window System. The X server can create an X11 configuration file, which is a text file that contains the settings for the X server and the devices it communicates with. The X11 configuration file is usually located at /etc/X11/xorg.conf or
* /etc/X11/xorg.conf.d/. The X server can generate a default configuration file using the command Xorg
-configure, or it can be edited manually by the user or the system administrator. References
https://www.baeldung.com/linux/display-managers-explained
* https://quizlet.com/185979426/lx0-104-flash-cards/

質問 # 70
With IPv6, how many bits have been used for the interface identifier of an unicast address? (Specify the number using digits only.)

正解：

解説：
64
Explanation:
With IPv6, the interface identifier of an unicast address is typically a 64-bit value that is used to identify a host's network interface. The interface identifier can be derived from the MAC address of the network card, or it can be randomly generated or manually configured. The interface identifier is the rightmost 64 bits of the most commonly encountered address types, such as global unicast (2000::/3) and link-local (fe80::/10). The interface identifier is different from the network prefix, which is the leftmost bits of the address that indicate the network or subnet to which the host belongs. The network prefix can vary in length, depending on the address type and the subnetting scheme. The network prefix and the interface identifier are separated by a double colon (::) in the IPv6 address notation. For example, in the address
2001:db8:1234:5678:abcd:ef12:3456:7890, the network prefix is 2001:db8:1234:5678 and the interface identifier is abcd:ef12:3456:7890. References:https://study-ccna.com/ipv6-interface-identifier/
https://networklessons.com/ipv6/ipv6-eui-64-explained

質問 # 71
Where are user specific crontabs stored?

• A. In the file /var/cron/user-crontab which is shared by all users.
• B. As individual per-user files within /var/spool/cron.
• C. In the .crontab file in the user's home directory.
• D. As individual per-user files in /etc/cron.user.d.
• E. In the database file /etc/crontab.db which is shared by all users.

正解：B

解説：
The user-specific crontab files are stored in the /var/spool/cron/crontabs directory, where each file is named after the username of the owner. These files are not meant to be edited directly, but rather through the crontab command. The other options are either incorrect or non-existent locations for user crontab files. Reference:
Where is the user crontab stored?
crontab running as a specific user
Location of the crontab file
Where is the User Crontab Stored?

質問 # 72
What is true regarding public and private SSH keys? (Choose two.)

• A. To maintain the private key's confidentiality, the SSH key pair must be created by its owner.
• B. The private key must never be revealed to anyone.
• C. For each user account, there is exactly one key pair that can be used to log into that account.
• D. Several different public keys may be generated for the same private key.
• E. To allow remote logins, the user's private key must be copied to the remote server.

正解：A、B

解説：
Explanation/Reference:

質問 # 73
Which of the following are syslog facilities? (Choose TWO correct answers.)

• A. local5
• B. mail
• C. postmaster
• D. remote
• E. advanced

正解：A

解説：
https://learning.lpi.org/en/learning-materials/102-500/108/108.2/
The syslog facilities are predefined categories of messages that can be used to classify the source and type of the log events12. The syslog facilities are defined by the syslog protocol and are standardized across different implementations of syslog12. The syslog facilities are:
auth: Security and authorization messages, such as login failures or sudo usage12.
authpriv: Same as auth, but used for private security messages that should not be available to all users12.
cron: Messages from the cron daemon, such as scheduled jobs or errors12.
daemon: Messages from system daemons, such as sshd or ntpd12.
kern: Messages from the kernel, such as boot messages or hardware errors12.
lpr: Messages from the line printer subsystem, such as print jobs or errors12.
mail: Messages from the mail subsystem, such as sendmail or postfix12.
news: Messages from the network news subsystem, such as news servers or clients12.
syslog: Messages generated internally by the syslog daemon, such as configuration errors or restarts12.
user: Messages from user-level processes, such as applications or scripts12.
uucp: Messages from the Unix-to-Unix copy subsystem, such as file transfers or errors12.
local0 to local7: Custom facilities that are not used by any system processes and can be assigned to user applications or scripts123.
Therefore, the correct answers are A. local7 and B. mail, as they are both valid syslog facilities. The other options are not syslog facilities and are either made up (C. advanced and E. remote) or refer to a specific process rather than a category of messages (D. postmaster).

質問 # 74
Which of the following tasks can the date command accomplish? (Choose two.)

• A. Set the system's date and time.
• B. Calculate the time span between two dates.
• C. Set the system's date but not the time.
• D. Print a calendar for a month or a year.
• E. Display time in a specific format.

正解：A、E

質問 # 75
Which of the following steps prevents a user from obtaining an interactive login session?

• A. Add the user to /etc/noaccess.
• B. Run the command chsh -s /bin/false with the user name.
• C. Remove the user from the group staff.
• D. Create a .nologin file in the user's home directory.
• E. Set the UID for the user to 0.

正解：B

質問 # 76
What is true about the file .profile in a user's home directory?

• A. It must be readable for its owner only.
• B. It must call the binary of the login shell.
• C. It must use a valid shell script syntax.
• D. It must start with a shebang.
• E. It must be executable.

正解：A

質問 # 77
What is the lowest numbered unprivileged TCP port? (Specify the number in digits only.)

正解：

解説：
1024

質問 # 78
What command should be used to print a listing of email in the system's mail queue?

• A. lpq
• B. mlq
• C. mailq
• D. sendmail -l

正解：C

質問 # 79
When the command echo $ outputs 1, which of the following statements is true?

• A. It is the process ID of the current shell.
• B. It is the exit value of the echo command.
• C. It is the exit value of the command executed immediately before echo.
• D. It is the process ID of the echo command.

正解：C

質問 # 80
When the command echo $$ outputs 12942, what is the meaning of 12942?

• A. It is the process ID of the last command which has been placed in the background.
• B. It is the process ID of the last command executed.
• C. It is the process ID of the current shell.
• D. It is the process ID of the echo command.

正解：C

解説：
In bash, the PID of a shell script's subshell process is stored in a special variable called $$. This variable is read-only, and you cannot modify it in a shell script1. You can use echo $$ to get the PID of the current bash shell you are using2. Therefore, when the command echo $$ outputs 12942, it means that the PID of the current shell is 12942. Reference:
[LPI Linux Essentials - Topic 103: Command Line Basics]
[Bash Special Parameters]
How to get the process ID (PID) of a shell script
How to know the process id of current bash session?

質問 # 81
The system's timezone may be set by linking /etc/localtime to an appropriate file in which directory? (Provide the full path to the directory, without any country information)

正解：

解説：
usrsharezoneinfo
Explanation:
The /usr/share/zoneinfo directory contains the binary time zone files that are used by the system to determine the local time for any region. The files are organized in subdirectories by continent, country, or ocean. Some files represent the standard time zones, while others may have historical or political variations. To set the system's timezone, one can create a symbolic link from /etc/localtime to the appropriate file in the /usr/share/zoneinfo directory. For example, to set the timezone to America/New_York, one can use the command sudo ln -sf /usr/share/zoneinfo/America/New_York /etc/localtime. Alternatively, one can use the timedatectl command to set the timezone without creating the link manually. Reference:
How to Set or Change the Time Zone in Linux | Linuxize
4 Ways to Change the Timezone in Linux - wikiHow

質問 # 82
......

Lpi 102-500試験は、90分以内に回答する必要がある60個の多肢選択問題と穴埋め問題から構成されています。試験は、Linuxカーネル、システム起動、ユーザー管理、ファイルのアクセス権、ファイルシステム、ネットワークプロトコル、トラブルシューティングなどの広範なトピックをカバーしています。試験に合格し、LPIC-1認定を取得するには、これらのコンセプトについて十分な理解が必要です。

LPIC-1試験102は、Linux管理に関連する幅広いトピックをカバーする包括的なテストです。この試験はいくつかのセクションに分かれており、それぞれがLinux管理の異なる側面に焦点を当てています。対象となるトピックには、ネットワーキング、ファイルシステムとストレージ、セキュリティ、トラブルシューティングが含まれます。

 

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