Pass the LPI LPIC-2 Certified Linux Engineer 202-450 Questions and answers with CertsForce

The cache_dir directive in the Squid configuration file specifies the type, location, size, and structure of the cache directory. The ufs type indicates that Squid uses the UNIX file system to store the cache files. The /var/spool/squid3/ is the path to the cache directory. The 1024 is the size of the cache in megabytes. The 16 and 256 are the number of first-level and second-level subdirectories that Squid creates under the cache directory.

Squid uses hexadecimal numbers to name the subdirectories, from 00 to FF. Therefore, there will be 16 first-level subdirectories, named 00, 01, 02, …, 0E, 0F. Under each first-level subdirectory, there will be 256 second-level subdirectories, named 00, 01, 02, …, FE, FF. For example, the subdirectory /var/spool/squid3/0F/FF will contain the cache files whose hash values end with 0FFF.

Therefore, the correct answer is A. 0F and E. 00, as they are the names of the first-level subdirectories that will exist directly within the directory /var/spool/squid3/. The other options are either invalid or second-level subdirectories that will not exist directly within the directory /var/spool/squid3/.

The http_access directive for Squid allows or denies access to the web resources based on defined access control lists (ACLs). The syntax of the http_access directive is:

http_access allow|deny [!]aclname …

The directive takes one or more ACL names as arguments, separated by spaces. The first argument is either allow or deny, indicating the action to be taken if the ACLs match. The optional ! character before an ACL name negates the result of that ACL.

To allow users in the ACL named sales_net to only access the Internet at times specified in the time_acl named sales_time, the correct http_access directive is:

http_access allow sales_net sales_time

This directive means that if the client IP address matches the sales_net ACL and the request time matches the sales_time ACL, then the access is allowed. Otherwise, the access is denied or the next http_access directive is evaluated.

Samba cannot use /etc/passwd and /etc/shadow directly because they store passwords in a different format than CIFS. CIFS passwords are encrypted using a one-way hash function, while Unix passwords are encrypted using a two-way cipher. Therefore, Samba needs a separate password file that stores the CIFS passwords in a compatible format. This file is usually called smbpasswd and can be created or updated using the smbpasswd command123 References:

Chapter 9. Users and Security - Samba

smbpasswd - Samba

Chapter 20. samba authentication - linux-training.be

Chapter 9. Users and Security - Samba3

Chapter 9. Users and Security - Samba

The command that creates a SSH key pair is ssh-keygen. This command generates a public and a private key file that can be used for SSH authentication. The command can take various options to specify the algorithm, the file name, the passphrase, and other parameters for the key pair. For more information, see the web search results below or the man page of ssh-keygen.

How to Use ssh-keygen to Generate a New SSH Key?

The PAM module that sets and unsets environment variables is pam_env. This module allows the (un)setting of environment variables based on the rules specified in the configuration file /etc/security/pam_env.conf or an alternative file. The module can also read a file with simple KEY=VAL pairs on separate lines (/etc/environment by default) or a user-specific file ($HOME/.pam_environment by default). The pam_env module supports the use of previously set environment variables as well as PAM_ITEMs such as PAM_RHOST. The pam_env module should be the last one on the stack, as setting PAM environment variables can have side effects on other modules. The pam_env module provides the auth and session module types. References:

pam_env - PAM module to set/unset environment variables

pam_env(8) - Linux manual page

 A Fail2Ban jail is a combination of a filter and one or several actions. A filter defines a regular expression that matches a pattern corresponding to a failed login attempt or another suspicious activity. Actions define commands that are executed when the filter catches an abusive IP address. A jail can have active or inactive status1 References: 1: Fail2Ban Jails Management | Plesk Obsidian documentation 

 After running ssh-keygen and accepting the default values, the following files are changed or created in the user’s home directory under the .ssh subdirectory:

~/.ssh/id_rsa: This file contains the private key of the user, which is used for authenticating the user to a remote server. The private key is encrypted with a passphrase, which can be left empty for convenience, but this is not recommended for security reasons. The private key should be kept secret and protected by the user, and should not be copied or shared with anyone else.

~/.ssh/id_rsa.pub: This file contains the public key of the user, which is used for verifying the user’s identity by the remote server. The public key can be copied and distributed to any server that the user wants to access via SSH. The public key can also be appended to the ~/.ssh/authorized_keys file on the remote server, which allows the user to log in without entering a password.

The other options are not correct. There is no file called ~/.ssh/id_rsa.key, ~/.ssh/id_rsa.prv, or ~/.ssh/id_rsa.crt created by ssh-keygen. The .key, .prv, and .crt extensions are not used by ssh-keygen, and they may be confused with other types of keys or certificates.

References:

How to Use ssh-keygen to Generate a New SSH Key?

How To Set Up SSH Keys

SSH Essentials: Working with SSH Servers, Clients, and Keys

 OpenVAS is a network security scanner project that, at the core, is a server with a set of network vulnerability tests (NVTs) to detect security problems in remote systems and applications. It is an open-source tool that was forked from Nessus, a popular commercial scanner. OpenVAS can perform comprehensive scans of networks and hosts, as well as web application scanning and compliance testing. It also provides a graphical user interface (GUI) and a command-line interface (CLI) for managing scans and reports. References:

Greenbone Vulnerability Management - Gentoo wiki

The Best Network Vulnerability Scanners Tested in 2023 - Comparitech

 A certificate signing request (CSR) is a message sent from an applicant to a certificate authority (CA) in order to apply for a digital identity certificate. The CSR contains information about the applicant’s identity, such as domain name, organization, location, etc., as well as the applicant’s public key. The CSR is digitally signed by the applicant using their private key, which proves that they own the corresponding public key. The CA will verify the CSR and issue a certificate if the applicant meets the requirements. The certificate will contain the applicant’s public key and identity information, as well as the CA’s digital signature, which validates the certificate. References: LPIC-2 Exam 202 Objectives, What is a Certificate Signing Request (CSR)? Do I need one?

 The error message in the image is saying that the program vsftpd is unable to find the required shared library file. This is because the program is running in a chroot jail, which restricts the program’s access to the file system. To fix this error, the required library file must be copied to the appropriate lib directory in the chroot jail. This will allow the program to access the file and run properly. References:

LPIC-2 Overview

LPIC-2 201-450

LPIC-2 202-450