Free Practice Questions for LPI 202-450 Exam

 PAM modules are organized and stored as shared object files within the /lib/ directory hierarchy. A shared object file is a file that contains executable code and data that can be loaded into memory and used by one or more programs. This allows PAM modules to be dynamically loaded and unloaded by the PAM library as needed, without requiring recompilation or relinking of the programs that use them. The /lib/ directory hierarchy contains subdirectories for different architectures and operating systems, such as /lib/x86_64-linux-gnu/ or /lib64/. The PAM modules are usually located in a subdirectory named security, such as /lib/x86_64-linux-gnu/security/ or /lib64/security/. The PAM modules have names that start with pam_ and end with .so, such as pam_unix.so or pam_cracklib.so12.

References:

PAM Modules: A section from the Linux-PAM System Administrators’ Guide that explains what PAM modules are, how they are named, and where they are located.

An introduction to Pluggable Authentication Modules (PAM) in Linux: An article from Red Hat that introduces the concept and usage of PAM in Linux, which includes a description of PAM modules and their location.

 A route to the destination fe80::/10 will appear in the Linux routing table after activating IPv6 on a router’s network interface, even when no global IPv6 addresses have been assigned to the interface. This is because fe80::/10 is the prefix for link-local addresses in IPv6, which are automatically configured on any interface that supports IPv6. Link-local addresses are used for communication within the same link or subnet, and are not routable beyond the local network. Link-local addresses have the format fe80::interface identifier, where the interface identifier is usually derived from the MAC address of the interface. Link-local addresses are useful for purposes such as neighbor discovery, router advertisement, and address autoconfiguration. Every IPv6-enabled interface must have a link-local address, even if it also has other types of addresses.

The other options are not correct. 0::/128 is the unspecified address, which is used as a placeholder when no address is available. It is not a valid destination for a route. 0::/0 is the default route, which matches all destinations. It is not automatically added to the routing table when IPv6 is enabled on an interface. fe80::/64 is not a valid prefix for link-local addresses, as it is too specific. Link-local addresses use the prefix fe80::/10, which covers the range from fe80:: to febf::. 2000::/3 is the prefix for global unicast addresses, which are routable on the public Internet. They are not automatically configured on an interface, unless stateless address autoconfiguration (SLAAC) or DHCPv6 is used.

References:

IPv6 Link-Local Addresses - PacketLife.net

IPv6 Addressing and Basic Connectivity Configuration Guide, Cisco IOS XE Gibraltar 16.12.x - IPv6 Addressing [Cisco IOS XE 16] - Cisco

IPv6 Addressing and Subnetting

According to the OpenLDAP Software 2.6 Administrator’s Guide1, the default access control policy is allow read by all clients. This means that if there is no access directive, any client can read any entry or attribute in the directory, but cannot modify or delete them. Therefore, option C is the correct answer, as it represents this policy. Option A is incorrect, as it grants write access to all clients, which is not the default. Option B is incorrect, as it denies access to all clients, which is also not the default. Option D is incorrect, as it grants read and write access only to the rootdn, which is the superuser of the directory, and denies access to all other clients.

References:

OpenLDAP Software 2.6 Administrator’s Guide: Access Control: The official documentation of OpenLDAP on how to configure access control for the directory server.

 The dig tool is a command-line utility that can query DNS servers and display the results in a human-readable format. The output of dig includes the following sections:

The header section, which shows the query parameters and response status.

The question section, which repeats the query name and type.

The answer section, which shows the resource records that match the query.

The authority section, which shows the authoritative name servers for the queried domain.

The additional section, which shows any additional records that may be useful.

The output format of dig is similar to the image provided in the question, which shows the following information:

The query was for the A record of www.lpi.org.

The response was received from the DNS server 8.8.8.8.

The response had an opcode of QUERY, a status of NOERROR, and a flags of QR RD RA.

The response had 1 question, 1 answer, 0 authority, and 0 additional records.

The answer record was www.lpi.org. 300 IN A 104.21.23.156, which means that the IP address of www.lpi.org is 104.21.23.156 and has a time-to-live of 300 seconds.

References: dig manual page, dig tutorial

The option in named.conf that specifies which hosts are permitted to ask for domain name information from the server is allow-query. The allow-query option is used to define an access control list (ACL) that matches the source IP address of the DNS query. The ACL can be a list of IP addresses, networks, keywords, or predefined ACL names. The default value of allow-query is any, which means that any host can query the server. However, this can pose a security risk, as the server may be exposed to unwanted or malicious queries. Therefore, it is recommended to restrict the allow-query option to only the hosts that need to access the server, such as the local network or trusted clients. For example, the following option allows only the hosts in the 192.168.1.0/24 network and the localhost to query the server:

allow-query { 192.168.1.0/24; localhost; };

The other options are not valid in named.conf. allowed-hosts, accept-query, permit-query, and query-group are not recognized keywords by BIND.

References:

LPIC-2 exam 202 objectives, topic 208.1, “Implementing a web server”

BIND 9 Administrator Reference Manual, chapter 6, “Access Control Lists and TSIG”

How to Configure DNS Server with TSIG on CentOS 8

The rpc.idmapd service is a new component of NFSv4 that does not exist in NFSv3. It is responsible for mapping user and group IDs between the NFS client and server, using string names instead of numeric values. This allows for better security and compatibility across different systems. The rpc.idmapd service runs on both the NFS client and server and communicates with each other using the NFSv4 protocol. The other services, rpc.statd, nfsd, and rpc.mountd, are common to both NFSv3 and NFSv4, although they have some differences in functionality and behavior. References: 1, 2, 3

The /etc/sysct1.conf file is used to configure kernel parameters at runtime. The net.ipv4.ip_forward parameter controls whether IP packet forwarding is enabled for IPv4. Setting it to 1 enables packet forwarding, while setting it to 0 disables it. This setting is applied at boot time and persists across system restarts. The other options are either incorrect or temporary solutions that do not survive a reboot. References: LPIC-2 201 exam objectives, LPIC-2 201-450 Exam Prep: Network Configuration

 The sender_canonical_maps parameter on a Postfix server specifies an optional address mapping that applies when mail is delivered (sent) from the server. This mapping can be used to rewrite the sender address of outgoing messages to a different format or domain. For example, the following sender_canonical_maps entry will rewrite the sender address from user@localdomain to user@example.com:

user@localdomain user@example.com

The sender_canonical_maps parameter only affects the sender address and not the recipient address. The recipient address can be modified by other parameters such as recipient_canonical_maps or virtual_alias_maps.

References: You can learn more about sender_canonical_maps and other Postfix address rewriting parameters from the following sources:

Postfix Address Rewriting

Postfix Configuration Parameters

Postfix Generic Mapping for Outgoing SMTP Mail

 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

 The option within the ISC DHCPD configuration file that defines the IPv4 DNS server address(es) to be sent to the DHCP clients is domain-name-servers. This option takes one or more IPv4 addresses as arguments and specifies the DNS servers that the client should use for name resolution. The domain-name-servers option is part of the standard DHCP options defined in RFC 2132 and is supported by the ISC DHCP server. The domain-name-servers option can be specified globally, per subnet, per shared network, per group, or per host in the dhcpd.conf file. For example, the following line in the dhcpd.conf file will assign the DNS servers 192.168.1.1 and 192.168.1.2 to all DHCP clients:

option domain-name-servers 192.168.1.1, 192.168.1.2;

References:

ISC DHCP 4.4 Manual Pages - dhcp-options

[RFC 2132 - DHCP Options and BOOTP Vendor Extensions]

isc-dhcp-server - Community Help Wiki - Official Ubuntu Documentation