LPIC-2 Certified Linux Engineer 202-450 LPI Study Notes

A zone file is a text file that defines a portion of the DNS namespace, called a zone. A zone file contains resource records that map domain names to IP addresses or other information. A zone file must follow the rules of the DNS hierarchy, which means that it can only contain records for names that are within the zone’s domain. For example, a zone file for example.com can only contain records for names that end with example.com, such as www.example.com or mail.example.com. It cannot contain records for names that are outside the zone’s domain, such as google.com or example.net. This is because the DNS server that hosts the zone file is only authoritative for the zone’s domain, and not for any other domains. If a zone file contains records for names that are outside the zone’s hierarchy, it will cause errors and inconsistencies in the DNS resolution process.  References: LPIC-2 202 exam objectives, DNS zone file format, DNS hierarchy

 The ldappasswd command is an OpenLDAP client tool that can be used to change the password for an LDAP entry. It can be used to change the password of the user who is binding to the LDAP server, or the password of another user if the bind user has sufficient privileges. The ldappasswd command requires the user to specify the LDAP server location, the bind DN and password, the old password, and the new password. The old and new passwords can be given on the command line, through prompts, or from files. The ldappasswd command can also use SASL authentication mechanisms instead of simple authentication. The ldappasswd command follows the general syntax of:

ldappasswd [options] [user]

where user is the DN of the entry whose password is to be changed. If omitted, the bind DN is used.

References:

• LPIC-2 Exam 202 Objectives, Objective 207.3: LDAP Operations
• How To Change Account Passwords on an OpenLDAP Server, DigitalOcean
• ldappasswd: change the password of an LDAP entry, openldap-clients Manual Page
• How To Change an OpenLDAP Password, Tyler’s Guides

The commands nc and telnet can be used to connect and interact with remote TCP network services. nc stands for netcat, a utility that can read and write data across network connections using TCP or UDP protocols. telnet is a client-server protocol that allows a user to communicate with a remote host using a virtual terminal. Both commands can be used to test the connectivity and functionality of network services such as web servers, mail servers, FTP servers, etc. by specifying the host name or IP address and the port number of the service. References:

• LPIC-2 exam 201 topics, section 205.1, “Use and configure network monitoring tools”.
• LPIC-2 exam 202 topics, section 208.1, “Implementing a web server”.
• Linux Essentials 010 exam objectives, section 4.3, “Basic network configuration and troubleshooting”.

The .htaccess file in the directory is configured to require a valid user. The .htpasswd file contains the username and password for usera. Therefore, usera can access the site using the password s3cr3t. References:

• LPIC-2 Overview
• LPIC-2 202-450
• Password Protecting Your Pages with htaccess