202-450 Exam Dumps : LPIC-2 - Exam 202 (part 2 of 2), version 4.5

The Require directive in mod_authz_core selects which authenticated users can access a resource. The directive takes one or more arguments that specify the authorization provider and the criteria for granting access. Some of the built-in authorization providers are:

• all: This provider matches all users, regardless of the criteria. It can be used to grant or deny access to everyone. For example, Require all granted allows access to everyone, while Require all denied denies access to everyone.
• ip: This provider matches the client IP address against a list of IP addresses, network/netmask pairs, or CIDR specifications. It can be used to allow or deny access based on the client’s location. For example, Require ip 192.168.1.0/24 allows access only to clients from the 192.168.1.0/24 subnet.
• host: This provider matches the client hostname against a list of domain names. It can be used to allow or deny access based on the client’s DNS name. For example, Require host example.com allows access only to clients whose hostname ends with example.com.
• local: This provider matches the client IP address against the server IP address. It can be used to allow or deny access based on whether the client is local or remote. For example, Require local allows access only to clients that connect to the server via the loopback interface.
• user: This provider matches the authenticated username against a list of usernames. It can be used to allow or deny access based on the user identity. For example, Require user alice bob allows access only to users alice and bob.
• group: This provider matches the authenticated user’s group membership against a list of groups. It can be used to allow or deny access based on the user’s group affiliation. For example, Require group admins allows access only to users who belong to the admins group.
• valid-user: This provider matches any authenticated user, regardless of the username. It can be used to allow or deny access based on the user authentication status. For example, Require valid-user allows access to any user who can provide valid credentials.
• expr: This provider evaluates an expression and grants or denies access based on the result. It can be used to implement complex logic based on various variables and functions. For example, Require expr "%{REQUEST_METHOD} == 'GET' && %{TIME_HOUR} < 12" allows access only to GET requests made before noon.
• method: This provider matches the request method against a list of methods. It can be used to allow or deny access based on the type of request. For example, Require method GET POST allows access only to GET and POST requests.
• regex: This provider matches the request URI against a regular expression. It can be used to allow or deny access based on the pattern of the request. For example, Require regex ^/admin/.* allows access only to requests that start with /admin/.

Therefore, the correct strings that can be used as an argument to Require are B, C, and E. Statement A is false because method is not a valid argument to Require, but a separate authorization provider. Statement D is false because header is not a valid argument to Require, but a variable that can be used in an expression.

References:

• mod_authz_core - Apache HTTP Server Version 2.4
• Access Control - Apache HTTP Server Version 2.4

The commands nc and telnet can be used to connect and interact with remote TCP network services. nc stands for netcat, a utility that can read and write data across network connections using TCP or UDP protocols. telnet is a client-server protocol that allows a user to communicate with a remote host using a virtual terminal. Both commands can be used to test the connectivity and functionality of network services such as web servers, mail servers, FTP servers, etc. by specifying the host name or IP address and the port number of the service. References:

• LPIC-2 exam 201 topics, section 205.1, “Use and configure network monitoring tools”.
• LPIC-2 exam 202 topics, section 208.1, “Implementing a web server”.
• Linux Essentials 010 exam objectives, section 4.3, “Basic network configuration and troubleshooting”.

The tool dig, which stands for domain information groper, is a command-line utility that provides the most information when performing DNS queries, without any options. Dig can query any type of DNS record and display the full response from the DNS server, including the header, question, answer, authority, and additional sections. Dig can also show the query time, server address, response code, flags, and statistics. Dig is a versatile and powerful tool that can be used for troubleshooting, testing, and debugging DNS issues123 References:

• dig(1) - Linux manual page
• How to Use the Dig Command on Linux
• How to use the dig command for DNS queries on Linux