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

 TSIG stands for Transaction SIGnature, which is a mechanism for authenticating DNS messages using a shared secret key and a cryptographic hash algorithm. TSIG can be used to secure DNS updates, zone transfers, and queries between DNS servers and clients. To configure a BIND server to use TSIG, the following parameters should be added to the named.conf file:

• A key statement that defines the name, algorithm, and secret of the TSIG key. The name can be any arbitrary string, the algorithm can be one of the supported algorithms such as hmac-md5, hmac-sha1, hmac-sha256, etc., and the secret can be a base64-encoded string that represents the shared secret key. For example:

key “server.example.com” { algorithm hmac-md5; secret “skrKc4DoTzi/takIlPi7JZA==”; };

• A server statement that specifies the IP address or hostname of the remote server that will use the TSIG key, and the name of the key that should be used for communication. For example:

server 192.168.1.10 { keys { “server.example.com”; }; };

• A zone statement that indicates the zone name, type, and file of the zone that will use TSIG, and the name of the key that should be used for updates or transfers. For example:

zone “example.com” { type master; file “example.com.zone”; allow-update { key “server.example.com”; }; allow-transfer { key “server.example.com”; }; };

Option E shows the correct configuration parameters that should be added if the server should use the algorithm hmac-md5 and the key skrKc4DoTzi/takIlPi7JZA==. The other options are incorrect because they either use the wrong syntax, the wrong algorithm, the wrong key name, or the wrong secret.

References:

• LPIC-2 exam 202 objectives, topic 208.2, “Securing a DNS server”
• BIND 9 Administrator Reference Manual, chapter 6, “Access Control Lists and TSIG”
• How to Configure DNS Server with TSIG on CentOS 8

 The Apache HTTPD configuration directive that specifies the RSA private key that was used in the generation of the SSL certificate for the server is SSLCertificateKeyFile1. This directive sets the file path and name of the file containing the server private key2. The private key is used to decrypt the data that is encrypted with the public key contained in the certificate1. The private key must match the certificate, otherwise an error will occur when starting the server2. The other options are not valid directives for Apache HTTPD. References:

• mod_ssl - Apache HTTP Server Version 2.4
• Why is SSLCertificateKeyFile needed for Apache? - Stack Overflow

Sieve is a language for filtering and sorting email messages on a mail server. Sieve core filters are the basic actions that can be applied to a message that matches a set of conditions. The following actions are available in Sieve core filters:

• discard: This action discards the message silently, without sending any notification to the sender or the recipient. This action is useful for deleting spam or unwanted messages.
• fileinto: This action delivers the message to a specified mailbox. The mailbox can be an existing one or a new one that is created by the action. This action is useful for organizing messages into different folders based on their content or headers.
• reject: This action rejects the message and sends a notification to the sender with a specified reason. The message is not delivered to the recipient. This action is useful for informing the sender that the message was not accepted due to some policy or error.

The other options are not valid actions in Sieve core filters. drop, relay, and fileinto are not recognized keywords by Sieve.

References:

• Sieve: An Email Filtering Language, section 2.10, “Actions”
• Sieve Tutorial, section 4, “Actions”