Master the LPI 202-450 Exam: Essential Study Tips and Strategies

The option for BIND that is required in the global options to disable recursive queries on the DNS server by default is recursion no;. This option tells the server not to provide recursive query behavior to any client, unless overridden by a view or a zone statement. Recursive queries are queries that the server will try to resolve by contacting other servers if it does not have the answer in its cache or zones. Disabling recursive queries can improve the security and performance of the server, especially if it is only meant to serve authoritative zones123 References:

• BIND: Stop Recursion DNS Under Linux / UNIX - nixCraft
• How to Disable External DNS Recursion in BIND? | DeviceTests
• bind - How to Disable External DNS recursion? - Ask Ubuntu

 The command exportfs is used to configure which file systems a NFS server makes available to clients. The exportfs command maintains a table of exported file systems in the /etc/exports file, which specifies the directories to be shared and the options for each host or network. The exportfs command can also be used to add, remove, or refresh the exported file systems without restarting the NFS service123 References:

• 8.6. Configuring the NFS Server - Red Hat Customer Portal
• How to configure NFS on Linux - Learn Linux Configuration
• How to configure Network File System on Linux | Enable Sysadmin

 In the context of configuring Nginx for reverse proxy, the proxy_pass directive is used to specify the protocol and address of a proxied server and an optional URI to which a location should be mapped. So, in the provided configuration sample, “proxy_pass” is the missing keyword that should precede “http://proxiedserver:8080;”.

References:

• [NGINX Docs | NGINX Reverse Proxy]: The official documentation of Nginx on how to set up a reverse proxy with Nginx.
• [How To Configure Nginx as a Web Server and Reverse Proxy for Apache on One Ubuntu 20.04 Server | DigitalOcean]: A tutorial from DigitalOcean on how to configure Nginx as a web server and reverse proxy for Apache on Ubuntu 20.04, which includes the use of the proxy_pass directive.

To join a file server to an Active Directory domain, the smb.conf file must specify the realm and the workgroup parameters correctly. The realm parameter is the DNS name of the Active Directory domain, in uppercase letters. The workgroup parameter is the NetBIOS name of the domain, which is usually the first part of the DNS name, but can be different. For example, if the DNS name of the domain is intra.example.com, the NetBIOS name could be INTRA or something else. To find out the NetBIOS name of the domain, you can use the command net ads info on a Linux machine that has Samba installed, or the command nltest /dsgetdc:intra.example.com on a Windows machine that is joined to the domain. The other options are either incorrect or irrelevant for this question. 

According to the configuration, the postmaster address is set to postmaster@domain.com. This means that any system-generated messages or notifications sent to the administrator of this domain will use this address as the sender. The postmaster address is also used to receive messages from external senders who need to contact the administrator for any reason, such as reporting spam or abuse. The postmaster address is a mandatory requirement for any mail server, as specified by the RFC 5321 standard. References:

• LPIC-2 exam 202 objectives, topic 207.3, Manage the postfix mail system
• RFC 5321, section 4.5.1, Postmaster Role

 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

 A glue record is a DNS record that provides the IP address of a nameserver that is a subdomain of the domain being queried. For example, if the domain example.com has nameservers ns1.example.com and ns2.example.com, then the .com nameservers will provide glue records for ns1.example.com and ns2.example.com, along with the NS records for example.com. This way, the resolver can find the IP address of the nameservers without having to query them first, which would create a circular dependency12

The format of a glue record is:

nameserver A IP address

where nameserver is the hostname of the nameserver, A is the record type for IPv4 address, and IP address is the IPv4 address of the nameserver3

Therefore, the only option that matches this format is A. ns1.lab A 198.51.100.53. The other options are either missing the record type, the IP address, or the dot after the nameserver name4 References:

• DNS Tools - Glue Records
• What Is Glue Record: Everything You Wanted To Know
• Glue Records and Dedicated DNS - NS1, an IBM Company
• DNS Record Types - DNSimple Help

Glue Records and Dedicated DNS - NS1, an IBM Company

The http_access directive for Squid allows or denies access to the web resources based on defined access control lists (ACLs). The syntax of the http_access directive is:

http_access allow|deny [!]aclname …

The directive takes one or more ACL names as arguments, separated by spaces. The first argument is either allow or deny, indicating the action to be taken if the ACLs match. The optional ! character before an ACL name negates the result of that ACL.

To allow users in the ACL named sales_net to only access the Internet at times specified in the time_acl named sales_time, the correct http_access directive is:

http_access allow sales_net sales_time

This directive means that if the client IP address matches the sales_net ACL and the request time matches the sales_time ACL, then the access is allowed. Otherwise, the access is denied or the next http_access directive is evaluated.

 In the ISC DHCPD server configuration, to always assign the IP address 192.168.1.2 to a host with the MAC address 08:00:2b:4c:59:23, you need to create a host declaration within your dhcpd.conf file. Option A provides the correct syntax for this configuration:

This configuration ensures that whenever a DHCP request is received from the MAC address specified, the ISC DHCPD server will always assign it the IP address 192.168.1.2.

References:

• ISC DHCP 4.1 Manual Pages - dhcpd.conf: The official documentation of ISC DHCPD on how to configure the dhcpd.conf file, which includes the host declaration syntax and examples.
• isc-dhcp-server: Using option dhcp-client-identifier in host declaration to identify a client: A question and answer from Server Fault on how to use the option dhcp-client-identifier in a host declaration, which also shows the use of the hardware-ethernet and fixed-address parameters.

Samba cannot use /etc/passwd and /etc/shadow directly because they store passwords in a different format than CIFS. CIFS passwords are encrypted using a one-way hash function, while Unix passwords are encrypted using a two-way cipher. Therefore, Samba needs a separate password file that stores the CIFS passwords in a compatible format. This file is usually called smbpasswd and can be created or updated using the smbpasswd command123 References:

• Chapter 9. Users and Security - Samba
• smbpasswd - Samba
• Chapter 20. samba authentication - linux-training.be

Chapter 9. Users and Security - Samba3

Chapter 9. Users and Security - Samba