Selected 202-450 LPIC-2 Certified Linux Engineer Questions Answers

The AuthType directive is used to specify the method of authentication for a directory or a location on the Apache HTTPD server. The directive has four possible values: None, Basic, Digest, and Form. Each value corresponds to a different module that implements the authentication mechanism.

• None: This value means that no authentication is required. This is the default value and it can be used to override any inherited authentication settings.
• Basic: This value means that the basic authentication method is used. This method is implemented by the mod_auth_basic module. It requires the user to enter a username and a password, which are sent to the server in plain text. Therefore, this method is not very secure and should be used with encryption, such as SSL or TLS.
• Digest: This value means that the digest authentication method is used. This method is implemented by the mod_auth_digest module. It requires the user to enter a username and a password, which are hashed by the client and the server using a nonce (a random number) and a realm (a name for the protected area). Therefore, this method is more secure than the basic method, as it prevents replay attacks and password sniffing.
• Form: This value means that the form authentication method is used. This method is implemented by the mod_auth_form module. It requires the user to fill out a web form with their credentials, which are sent to the server using the POST method. Therefore, this method is more flexible and user-friendly than the other methods, as it allows the use of custom forms and cookies.

References:

• AuthType Directive
• Authentication and Authorization - Apache HTTP Server Version 2.4
• How to Create and Use .htpasswd

 The mydestination parameter in the Postfix main.cf configuration file specifies the list of domains that are delivered via the $local_transport mail delivery transport. This means that Postfix will accept mail for those domains and deliver it to local mailboxes. To accept mail for both the old and new domain names, the mydestination parameter should include both domains, separated by commas. For example:

mydestination = olddomain.com, newdomain.com, localhost

This will allow Postfix to accept mail for user@olddomain.com and user@newdomain.com and deliver it to the same local user mailbox.

References:

• LPIC-2 Exam 202 Objectives, Objective 205.3: Managing a postfix server
• Postfix Basic Configuration, Postfix Documentation
• Postfix Configuration Parameters: mydestination, Postfix Documentation
• How to configure Postfix to receive mail for multiple domains, Server Fault

 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

 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