Free Practice Questions for LPI 202-450 Exam

When the rootdn and rootpw directives are not present in the slapd.conf file, the LDAP administrator account is defined in the file /etc/ldap.secret. This file contains the password for the LDAP root user, which is usually cn=admin,dc=example,dc=com. The file should be owned by root and have permissions of 600 to prevent unauthorized access. The file is referenced by the olcRootPW directive in the cn=config database, which is used to configure the LDAP server. The olcRootPW directive can also be set by using the ldappasswd command with the -Y EXTERNAL option, which allows the LDAP server to authenticate itself to itself using the SASL EXTERNAL mechanism12.

References:

How To Configure OpenLDAP and Perform Administrative LDAP Tasks | DigitalOcean: A tutorial from DigitalOcean on how to configure OpenLDAP and perform administrative LDAP tasks, which includes the use of the /etc/ldap.secret file and the ldappasswd command.

OpenLDAP Software 2.6 Administrator’s Guide: Configuring slapd: The official documentation of OpenLDAP on how to configure the slapd daemon, which includes the description of the olcRootPW directive and the SASL EXTERNAL mechanism.

The option in the sshd configuration file that instructs sshd to permit only specific user names to log in to a system is AllowUsers. This option can be followed by a list of user name patterns, separated by spaces, that are allowed to log in. For example:

AllowUsers alice bob

This will allow only alice and bob to log in via ssh. Any other user will be denied access. The AllowUsers option can also take the form USER@HOST to restrict logins to particular users from particular hosts. For example:

AllowUsers alice@192.168.1.* bob@example.com

This will allow alice to log in from any host in the 192.168.1.0/24 network, and bob to log in from the host example.com. The AllowUsers option can be used in conjunction with the DenyUsers option, which does the opposite. The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups.

References:

sshd_config - OpenSSH SSH daemon configuration file

Allow Or Deny SSH Access To A Particular User Or Group In Linux - OSTechNix

 After running ssh-keygen and accepting the default values, the following files are changed or created in the user’s home directory under the .ssh subdirectory:

~/.ssh/id_rsa: This file contains the private key of the user, which is used for authenticating the user to a remote server. The private key is encrypted with a passphrase, which can be left empty for convenience, but this is not recommended for security reasons. The private key should be kept secret and protected by the user, and should not be copied or shared with anyone else.

~/.ssh/id_rsa.pub: This file contains the public key of the user, which is used for verifying the user’s identity by the remote server. The public key can be copied and distributed to any server that the user wants to access via SSH. The public key can also be appended to the ~/.ssh/authorized_keys file on the remote server, which allows the user to log in without entering a password.

The other options are not correct. There is no file called ~/.ssh/id_rsa.key, ~/.ssh/id_rsa.prv, or ~/.ssh/id_rsa.crt created by ssh-keygen. The .key, .prv, and .crt extensions are not used by ssh-keygen, and they may be confused with other types of keys or certificates.

References:

How to Use ssh-keygen to Generate a New SSH Key?

How To Set Up SSH Keys

SSH Essentials: Working with SSH Servers, Clients, and Keys

In Apache HTTPD configuration, only one ServerName directive is allowed per VirtualHost block. The ServerName provides the hostname and port that the server uses to identify itself. If there are additional domain names pointing to the same virtual host, they should be added using the ServerAlias directive. For example, the following configuration would create a virtual host that responds to both www.example.com and www2.example.com:

ServerName www.example.com ServerAlias www2.example.com ServerAdmin webmaster@example.com DocumentRoot /var/www/ Require all granted

The ServerName and ServerAlias directives are usually included in such configuration files. To enable or disable a virtual host, we can use the a2ensite and a2dissite commands to create and remove the symbolic links in the sites-enabled directory. For more information about the ServerName and ServerAlias directives, you can refer to the following resources:

1: A Microsoft Learn article that explains the syntax and usage of the ServerName and ServerAlias directives on Windows Server.

2: A Stack Overflow question that discusses the difference between ServerName and ServerAlias in Apache configuration.

3: A Stack Overflow question that shows how to redirect ServerAlias to ServerName in Apache configuration.

The relayhost parameter in the Postfix configuration file (/etc/postfix/main.cf) specifies the hostname or IP address of an external SMTP server that will handle the outgoing emails for Postfix. This server is also known as a smarthost or a relayhost. By using a relayhost, Postfix can delegate the responsibility of delivering emails to remote destinations to another server that may have better network connectivity, security, or reputation. A relayhost can also provide authentication, encryption, or filtering services for Postfix. References:

Postfix Standard Configuration Examples

How to configure Postfix relayhost (smarthost) to send eMail using an external smptd