Chapter 2

Question 1

Describe the ways to start server programs in Linux.

Answer 1

Server programs in Linux can either run continually in the background as a daemon process or be started from a super-server daemon when requested by a client.

Question 2

Explain how clients know how to contact a server program.

Answer 2

Server applications listen for client connections on well-known ports. Clients must send a connection request to the server on the well-known port for the application they want to interact with.

Question 3

Explain the components commonly used in a LAMP stack.

Answer 3

The LAMP stack uses the Linux operating system, the Apache web server, the MySQL database server, and the PHP programming language to provide a platform for web applications.

Question 4

Describe the difference between a relational database and a NoSQL database.

Answer 4

A relational database stores data records in individual data tables. Each data type consists of one or more data fields that contain individual data elements. A data record is an instance of data for each data field in a table. A NoSQL database stores data values in documents. Each document is independent of all of the other documents in the database. Each document can also contain different data elements.

Question 5

Understand the ways a Linux server can share files in a local network. olders located on Windows servers.

Answer 5

Linux servers can use the nfs-utils package to communicate with other Linux servers to share folders using NFS. The local Linux server can mount folders from the remote Linux server as if they were local disks. Linux servers can also use the Samba package to share files on Windows local networks with Windows clients and servers as well as map f

Question 6

Understand which server packages are commonly used to support network features on a local network.

Answer 6

The DHCPd package provides DHCP server services to assign IP addresses to clients. The BIND package provides DNS server services to both clients and servers on a local network for hostname resolution. The net-snmp package allows you to implement remote device management using SNMP, and you can use the ntpd package to create an NTP time server for the local network.

Question 7

Describe how to create a network directory server using Linux.

Answer 7

The OpenLDAP package allows you to create an LDAP directory of users and devices on the local network. Clients and other servers can use the LDAP directory to authenticate users and devices on the network.

Question 8

Explain how to improve the performance of a network application.

Answer 8

For network applications in a high-volume environment, you can improve performance by implementing either a cluster or load balancing environment. In a cluster, you can split application functions between multiple servers by using a cluster package such as Apache Hadoop. With load balancing, you can distribute client connections between multiple servers using packages such as HAProxy and Linux Virtual Server (LVS).

Question 9

Which web server is used in the popular LAMP stack?

nginX
Apache
Lighthttpd
PostgreSQL

Answer 9

B. The Apache web server has gained popularity as being combined with the Linux OS, the MySQL database server, and the PHP programming server, making the LAMP stack. The nginX server is a newer web server that is gaining in popularity but is not part of the LAMP stack. The Lighthttpd web server has a small memory and CPU footprint, making it ideal for embedded systems but not for large-scale LAMP applications. The PostgreSQL package is a database server and not a web server.

Question 10

A ________ runs in the background and listens for client connection requests for a single application.

Daemon
Super-server
Shell

Answer 10

A. A daemon is a single application that runs in background listening for client connection requests, so option A is the correct answer. A super-server listens for more than one application, so option B doesn’t apply. The shell doesn’t listen for network connections; it launches applications interactively, so option C is incorrect. The graphical desktop also allows you to launch applications, but it doesn’t listen for client connection requests, so option D is incorrect.

Question 11

Which open source database provided fast performance and became a popular choice for web applications?

MongoDB
PostgreSQL
MySQL
NoSQL

Answer 11

C. When first released, the MySQL database server focused on speed, making it a popular choice for high-volume Internet web applications, so option C is correct. The MongoDB database server provides object-oriented database features but doesn’t focus on performance, so option A is incorrect. The PostgreSQL database focused on implementing fancy database features instead of speed, so option B is incorrect. NoSQL is a database storage method that incorporates object-oriented data records and is not a database server package itself, so option D is incorrect.

Question 12

How does a server know what client request is sent to which application daemon?

IP addresses
Ports
Ethernet addresses
Services

Answer 12

B. Linux services listen on well-known ports for requests from clients, so option B is correct. A server normally has a single IP address to support multiple applications, so option A is incorrect. The server also normally has only a single Ethernet address, so option C is incorrect. The clients can’t launch individual services on the server, so option D is incorrect.

Question 13

What popular open source web servers can also perform as a load balancer?

nginX
Apache
PostgreSQL
Lighthttpd

Answer 13

A. The nginX web server can serve as a load balancer and send client requests to multiple backend web servers, so option A is correct. The Apache and lighthttpd web servers don’t support this feature, so options B and D are incorrect. The PostgreSQL server is a database and not a web server, so option C is incorrect.

Question 14

What format does MongoDB use to store data elements in the database?

Relational
YaML
JSON

Answer 14

C. The MongoDB database server uses the JSON format for storing data records. The relational database is a type of database system and not a method for storing data, so option A is incorrect. YaML is a plaintext method for creating configuration files, but it is not used in MongoDB for storing data, so option B is incorrect. The MongoDB data is not normally encrypted, so option D is also incorrect.

Question 15

Which part of the Linux mail process is responsible for sending emails to remote hosts?

MUA
MTA
MDA
Evolution

Answer 15

B. The MTA package is responsible for connecting with remote mail hosts to deliver email messages, so option B is correct. The MUA allows clients to connect to the email server to read their messages, so option A is incorrect. The MDA allows you to create rules for processing mail locally, not to remote servers, so option C is incorrect. Evolution is an email MUA client application, not a server MTA package. The Evolution package is a graphical email client, so option D is incorrect.

Question 16

Which part of the Linux mail process allows you to create filters to automatically redirect incoming mail messages?

MUA
MTA
MDA
Evolution

Answer 16

C. The MDA allows you to create filters to match email messages to redirect to other folders, so option C is correct. The MUA is the user interface and doesn’t control how incoming mail is delivered by the server, so option A is incorrect. The MTA delivers email to remote hosts and accepts mail from remote hosts, so option B is incorrect. The Evolution package is a graphical MUA package for clients and does not allow you to create filters to deliver email messages, so option D is incorrect.

Question 17

What protocol should you use to mount folders from remote Linux servers on your local Linux server?

SNMP
NTP
DHCP
NFS

Answer 17

D. The NFS protocol is used to share folder areas on the network with clients, so option D is correct. SNMP is a network protocol used for managing remote devices, so option A is incorrect. NTP is a network protocol used for setting the time on servers, so option B is incorrect. DHCP is a network program used for assigning IP addresses to network devices, so option C is incorrect.

Question 18

The ________ software package allows your Windows workstations to mount a folder stored on a Linux server.

ntpd
Samba
DHCPd
Evolution

Answer 18

B. The Samba software package allows a Linux server to communicate with Windows servers and clients using the SMB protocol, so option B is correct. The ntpd daemon listens for requests from a remote time server, so option A is incorrect. The DHCPd package provides DHCP services on the Linux server to assign network IP addresses; it doesn’t allow workstations to map folders on the Linux server, so option C is incorrect. The Evolution package is a graphical desktop program used to access email in the mail folder and is not a server service, so option D is incorrect.

Question 19

Which two software packages are used in Linux to maintain log files? (Choose two.)

rsyslogd
journald
ntpd
DHCPd

Answer 19

A, B. The rsyslogd program is used by SysV init systems to log events, and the journald program is used by Systemd systems to log events, so options A and B are the correct answers. The ntpd program provides time services and not logging services, so option C is incorrect. The DHCPd program is used for assigning IP addresses on a local network and not for logging services, so option D is incorrect.

Question 20

Which software program should you load on your Linux server to synchronize its time with a standard time server?

DHCPd
BIND
ntpd
Samba

Answer 20

C. The ntpd service uses NTP to synchronize the server time with a remote system, so option C is correct. The DHCPd program assigns IP addresses to devices on the local network but not time, so option A is incorrect. The BIND program provides hostname resolution services but not time services, so option B is incorrect. The Samba package allows a Linux server to interact with Windows clients and servers, but it doesn’t provide time services, so option D is incorrect.

Question 21

What software package allows a Linux server to print to a network printer?

DHCPd
BIND
ntpd
CUPS

Answer 21

D. The CUPS application provides printer drivers and services that allow Linux systems to connect with local and remote printers, so option D is correct. The DHCPd program assigns IP addresses to devices on the local network but doesn’t connect to remote printers, so option A is incorrect. The BIND application provides hostname resolution services but can’t connect to printers, so option B is incorrect. The ntpd program allows you to synchronize the server time with a remote time clock but doesn’t connect to network printers, so option C is incorrect.

Question 22

If you see the named program running in the background on your Linux server, what service does it provide?

Network time
Hostname resolution
Dynamic IP address allocation
Printing

Answer 22

B. The named program is part of the BIND application, which provides hostname resolution services, so option B is correct. The ntpd program is what provides network time, so option A is incorrect. The DHCPd program provides dynamic IP address allocation on a local network, so option C is incorrect. The CUPS application provides printing services on a Linux system, so option D is incorrect.

Question 23

Which authentication package used to be called by the name “Yellow Pages”?

Samba
Kerberos
NIS
BIND

Answer 23

C. The NIS package was formerly called Yellow Pages (YP), but the name had to be changed due to trademark issues, so option C is correct. The Samba package, which provides Windows client and server services in Linux, refers to a popular Latin dance, not the Yellow Pages, so option A is incorrect. The Kerberos package, which does provide authentication services in Linux, refers to the three-headed hound that guards Hades, not the Yellow Pages, so option B is incorrect. The BIND application refers to binding a name to an IP address, which is a similar function to the Yellow Pages, but it wasn’t formerly called Yellow Pages, so option D is incorrect.

Question 24

What package do you need to install to allow your Linux server to provide IP addresses to clients on your local network?

DHCPd
BIND
ntpd
Evolution

Answer 24

A. The DHCPd program provides DHCP server services on a local network, so option A is correct. The BIND package provides hostname resolution services; it doesn’t assign IP addresses, so option B is incorrect. The ntpd package provides network time services but not address services, so option C is incorrect. Evolution is a client MUA package for reading email; it doesn’t provide IP addresses to clients, so option D is incorrect.

Question 25

The ________ package allows you to create a secure tunnel across a private network to access your local network remotely.

BIND
ntpd
OpenSSH
OpenSSL

Answer 25

C. The OpenSSH package allows you to use certificates to establish a secure connection between two devices on the network, so option C is correct. The BIND package provides hostname resolution, not secure connections, so option A is incorrect. The ntpd package provides time services on the network, not secure connections, so option B is incorrect. The OpenSSL package allows you to create certificates used for encrypted communication but doesn’t perform the communication itself, so option D is incorrect.

Question 26

What server role should you implement to block your local network clients from accessing sports websites during business hours?

A DHCP server
A web server
A web proxy
A container

Answer 26

C. A web proxy server allows you to intercept client web requests and block any requests based on rules you define, so option C is correct. A DHCP server assigns IP addresses to devices on the local network; it doesn’t intercept web requests, so option A is incorrect. A web server hosts websites but doesn’t intercept requests made by local clients, so option B is incorrect. A container allows developers to easily deploy web applications in different environments but doesn’t intercept web requests from local clients, so option D is incorrect.

Question 27

What server role should you implement to increase performance on your company’s website?

A load balancer
A web proxy
A DHCP server
A container

Answer 27

A. A load balancer sends client requests to one server within a cluster of servers to balance traffic among the servers, so option A is correct. A web proxy server intercepts web requests from clients but can only filter or pass the request to the destination host, so option B is incorrect. A DHCP server assigns IP addresses to devices on a local network but doesn’t help increase performance of network applications, so option C is incorrect. A container allows a developer to easily deploy web applications to different environments but can’t control what traffic goes to which server, so option D is incorrect.

Question 28

A ________ allows your developers to easily deploy applications between development, test, and production.

web proxy
DHCP server
container
cluster

Answer 28

C. A container allows developers to develop applications in a controlled environment that can easily be deployed to other servers, so option C is correct. A web proxy intercepts web requests from clients but doesn’t control how applications are deployed, so option A is incorrect. A DHCP server assigns IP addresses to devices on the local network but doesn’t control how applications are deployed, so option B is incorrect. A cluster can help with application performance by spreading the load among multiple servers but doesn’t control how developers deploy the application to the servers, so option D is incorrect.