LPI 202-450 Exam With Confidence Using Practice Dumps

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 security option in the smb.conf file determines how Samba authenticates users who try to access its shares. The value of security = share means that Samba does not require a valid username and password for each connection, but only for each share. This allows users to access shares anonymously, without providing any credentials. This is useful for setting up a guest printer service, where anyone can print to a shared printer without logging in. However, this option is deprecated and not recommended for security reasons. The other options are either invalid or irrelevant for this question.

 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