The top-level directory which contains the configuration files for CUPS is /etc/cups. CUPS stands for Common UNIX Printing System, which is the printer and print job manager for Linux. The /etc/cups directory contains several configuration files related to CUPS, such as cupsd.conf, which is the main configuration file for the cupsd print server daemon, and printers.conf, which contains the definition of the printers.The /etc/cups directory is part of the topic 108.4: Manage printers and printing, which is one of the objectives of the LPI Linux Administrator - 102 exam12.Reference:1:LPI Linux Administrator - 102 (LPIC-1)2:Exam 102 Objectives

The correct syntax for selecting specific columns from a table in SQL is to use the SELECT keyword followed by a comma-separated list of column names and then the FROM keyword followed by the table name. Therefore, the only option that follows this syntax is C. SELECT name, address FROM contacts; The other options are incorrect because they either use parentheses around the column names, which are not needed, or they omit the comma between the column names, which causes a syntax error.Reference: https://www.sqltutorial.org/sql-select/

https://www.w3schools.com/mysql/mysql_select.asp

UIDs and GIDs are two different types of identifiers for users and groups in Linux. They are not related to each other, and they do not affect each other's availability or functionality. A user can have the same UID as another user's GID, or vice versa, without any problem. The only restriction is that UIDs and GIDs must be unique within their own domain, i.e., no two users can have the same UID, and no two groups can have the same GID. Having the same UID as a GID does not imply any special relationship between the user and the group, nor does it grant any extra permissions or access rights.The user and the group are still treated as separate entities by the system123Reference:1: Linux sysadmin basics: User account management with UIDs and GIDs2: How to (Correctly) Change the UID and GID of a user/group in Linux3: Linux File Permission: uid vs gid - CBT Nuggets

The /etc/hosts.allow file contains a set of rules that specify which services and hosts are allowed to connect to the server by going through a TCP Wrapper program such as tcpd. TCP Wrappers are a security mechanism that can filter incoming requests based on the source address, destination address, and service name. TCP Wrappers can also perform logging, redirection, and execution of commands based on the rules.

The /etc/hosts.allow file has the following format:

service_list : host_list [ : option_list ]

The service_list is a comma-separated list of service names, such as sshd, telnet, or ftp. The host_list is a comma-separated list of host names, IP addresses, or network masks that are allowed to access the services. The option_list is an optional list of keywords that can modify the behavior of the rule, such as twist, spawn, deny, or allow.

For example, the following rule in /etc/hosts.allow allows ssh access from any host in the 192.168.1.0/24 network, and logs the connection attempt:

sshd : 192.168.1.0/255.255.255.0 : spawn /bin/echo %a from %h attempted to access %d >> /var/log/sshd.log

The /etc/hosts.allow file is processed before the /etc/hosts.deny file, which contains the rules for denying access to the server. If a request matches a rule in /etc/hosts.allow, it is granted access and the processing stops. If it does not match any rule in /etc/hosts.allow, it is checked against the rules in /etc/hosts.deny. If it matches a rule in /etc/hosts.deny, it is denied access and the processing stops. If it does not match any rule in either file, it is granted access by default.

LPI 102-500 Exam Objectives, Topic 110.3: Implement host security

LPI 102-500 Study Guide, Chapter 10: Securing Your System, Section 10.3: TCP Wrappers

hosts.allow man page