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- Herausgeber: Packt Publishing
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Master the concepts and techniques that will enable you to succeed on the SK0-004 exam the first time with the help of this study guide
Key Features
- Explore virtualisation, IPv4 & IPv6 networking, administration and more
- Enhancing limited knowledge of server configuration and function
- A study guide that covers the objectives for the certification examination
Book Description
CompTIA Server+ Certification is one of the top 5 IT certifications that is vendor neutral.System administrators opt for CompTIA server+ Certification to gain advanced knowledge of concepts including troubleshooting and networking.
This book will initially start with the configuration of a basic network server and the configuration for each of its myriad roles. The next set of chapters will provide an overview of the responsibilities and tasks performed by a system administrator to manage and maintain a network server. Moving ahead, you will learn the basic security technologies, methods, and procedures that can be applied to a server and its network. Next, you will cover the troubleshooting procedures and methods in general, and specifically for hardware, software, networks, storage devices, and security applications. Toward the end of this book, we will cover a number of troubleshooting and security mitigation concepts for running admin servers with ease. This guide will be augmented by test questions and mock papers that will help you obtain the necessary certification.
By the end of this book, you will be in a position to clear Server+ Certification with ease.
What you will learn
- Understand the purpose and role of a server in a computer network
- Review computer hardware common to network servers
- Detail the function and configuration of network operating systems
- Describe the functions and tasks of network operating system administration
- Explain the various data storage options on a computer network
- Detail the need for, and the functioning and application of, network and server security
- Describe the operational elements of a network provided by a server
- Explain the processes and methods involved in troubleshooting server issues
Who this book is for
This book is targeted towards professionals seeking to gain the CompTIA Server+ certification. People coming from a Microsoft background with basic operating system and networking skills will also find this book useful. Basic experience working with system administration is mandatory.
Das E-Book können Sie in Legimi-Apps oder einer beliebigen App lesen, die das folgende Format unterstützen:
Seitenzahl: 581
Veröffentlichungsjahr: 2019
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CompTIA Server+ Certification Guide
Copyright © 2019 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing or its dealers and distributors, will be held liable for any damages caused or alleged to have been caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
Commissioning Editor: Gebin GeorgeAcquisition Editor: Rohit RajkumarContent Development Editor: Ronn KurienTechnical Editor:Swathy MohanCopy Editor:Safis EditingProject Coordinator: Jagdish PrabhuProofreader: Safis EditingIndexer: Tejal Daruwale SoniGraphics:Tom ScariaProduction Coordinator: Arvindkumar Gupta
First published: February 2019
Production reference: 1250219
Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK.
ISBN 978-1-78953-481-8
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Contributors
About the author
Ron Price (Server+, A+, Network+, Security+, CCNA, MBA, AAGG) began his experience in computing as a programmer on a mainframe operating system project. He has experience in system design, database systems, operational administration and senior management. In addition to his writing, Ron is an instructor of information systems at Spokane Falls Community College.
About the reviewer
Christopher Rees is a lifelong learner, an IT technology leader, an author at Pluralsight, and a former law enforcement officer who focused on computer crime investigations. For the past 20 years, he has been working in the enterprise IT space and has trained over 100,000 people from around the world via the online training courses he's developed in the areas of networking, cybersecurity, and business continuity management.Married for more than 20 years with 3 beautiful children, Chris enjoys keeping fit, maximizing his time with his family and friends, and, of course, keeping up with the latest tech and industry trends.
Packt is searching for authors like you
If you're interested in becoming an author for Packt, please visit authors.packtpub.com and apply today. We have worked with thousands of developers and tech professionals, just like you, to help them share their insight with the global tech community. You can make a general application, apply for a specific hot topic that we are recruiting an author for, or submit your own idea.
Table of Contents
Title Page
Copyright and Credits
CompTIA Server+ Certification Guide
About Packt
Why subscribe?
Packt.com
Contributors
About the author
About the reviewer
Packt is searching for authors like you
Preface
Who this book is for
What this book covers
To get the most out of this book
Download the color images
Conventions used
Get in touch
Reviews
Section 1: System Architecture
Server Hardware
Server roles
Application servers
Database servers
Directory servers
File servers
Mail servers
Messaging servers
Network services servers
Print servers
Proxy server
Routing and Remote Access Service (RRAS)
Virtual server
Form factors
Tower servers
Rack mounts
Blade technology
Server power systems
Electrical power
AC versus DC / 110V versus 230V
Wye and delta
Negative 48V
One phase versus three phases
PSU
Wattage
The 80-plus certification
Selecting the right PSU
Redundancy
System heat
Cooling systems
Air cooling and air flow
Summary
Questions
Server Internals
CPUs
Multiprocessors
Symmetrical Multiprocessing (SMP) versus Asymmetrical Multiprocessing (ASMP)
SIMD, MISD, and MIMD
Multiple core processing
CPU packages and sockets
Cache memory
CPU cache memory
CPU cache memory levels
Write-back/write-through cache
Advanced RISC Machine (ARM) servers
CPU multiplier
CPU stepping
Main memory
RAM
Double Data Rate (DDR) RAM
RAM packaging
Memory timing
Error-correction code (ECC) versus non-ECC
Dual channel memory
Color-coded RAM slots
Buses, channels, and expansion slots
Bus width
Peripheral Component Interconnect (PCI) bus
PCI size and fit standards
PCI conventional
PCI-e
Expansion cards
Network interface controller (NIC)
Host Bus Adapter (HBA)
Redundant Array of Independent Disks (RAID) controller
Riser cards
USB interface and port
Configuration
BIOS
UEFI
Summary
Questions
Data Storage
Data storage devices and their specifications
Hard drive specifications
Form factors
Small form factor (SFF)
Large form factor (LFF)
HDD specification and configuration
Disk capacity – decimal versus binary
Hard disk drive (HDD) versus solid-state drive (SSD)
SSD specification and configuration
Hard disk interfaces
Data storage systems
Direct-attached storage (DAS)
Network-attached storage (NAS)
Storage area network (SAN)
SAN fabric
SAN communications
Logical Unit Number (LUN) zoning and masking
Filesystem
Operating systems and filesystems
File sharing
RAID
Striping and mirroring
RAID levels
RAID implementation
Disk quotas
Disk compression
High availability (HA)
The nines
Fault tolerance
Replacing failed components
Disk storage capacity planning
Other storage devices
Magnetic tape
Optical storage
Summary
Questions
Server Operating Systems
The network server
Server functions
Network server operating systems
Operating system (OS) functions
User/computer communications
Memory management
Dynamic loading and linking
Memory allocation
Control and coordination of hardware
The use of system resources
Internal and network file management
User, data, application, and resource security
Hardware configuration
The primary parts of an OS
The OS and hardware
Boot sequence
Firmware
Preparing a disk for the OS
Filesystems
Formatting
Filesystems by OS
Journaling
Special function filesystems
Network configuration
Configuring the hostname
Configuring a hostname on Windows Server
Configuring a hostname on a Linux server
User accounts
Creating a local user account
Creating a domain user account
Adding a workstation to a domain
Connecting to a network
Connecting a PC to a network
Adding server roles and features
Unattended and remote installations
NOS optimization
Summary
Questions
Addressing
IP addressing
IP version 4
The IPv4 address structure
Classful IP addressing
LAN addressing
Private IP addresses
Network and host IDs
Network Address Translation (NAT)
Collision domains
Broadcast domains
Classless Interdomain Routing (CIDR)
Subnetting
Subnets and hosts
Subnet masks
Network and broadcast addresses
Internet Protocol version 6 (IPv6)
The IPv6 address structure
Reserved prefixes
IPv6 address compression
IPv6 leading zero compression
IPv6 network ID
Address categories
MAC addressing
Address resolution
ARP
DNS
DNS search
Domain suffix
The Windows Internet Name Service (WINS)
Ports and protocols
Well-known ports
Registered ports
Summary
Questions
Cabling
Copper cabling
Twisted-pair cabling
Coaxial cabling
Network connectors
EIA/TIA 568 facility standards
Category cabling
Ethernet cable standards
Fiber-optic cabling
Fiber-optic cable modes
SM fiber-optic cable
MM fiber-optic cable
Fiber-optic cable connectors
Network cable installation
Summary
Questions
Section 2: Administration
Server Administration
Hardware administration
Network administration
Configuring, updating, and maintaining network hardware
KVM interfaces
Serial interfaces
Network-based hardware administration
Network-based operating system administration
Asset management
Information Technology Asset Management (ITAM)
IT life cycle asset management
Additional ITAM terms
System documentation
Service manuals
System and network documentation
System diagrams
System documentation
Other documents and documentation
Storing sensitive documentation
Summary
Questions
Server Maintenance
Change and patch management
Change control process
Patch management
OS updates
Device driver updates
Firmware updates
Hardware maintenance
Server monitoring systems
Light Emitting Diodes (LED) server status indicator
Liquid Crystal Display (LCD) messages
Beep codes
Replace failed components
Preventive maintenance
Fault tolerance and high availability
Clustering
Active/active versus active/passive clusters
Load balancing
Heartbeat
Hot and not hot
Hot swap
Non-hot swap
Service level agreements (SLA)
Summary
Questions
Virtualization
Virtual networking
Virtual network components
Virtual devices
Virtual servers
Hypervisors
Hosts and guests
Virtual machine (VM)
Hardware configuration for a virtual environment
Virtual resource allocation
Network connectivity
Virtual internetworking devices
Summary
Questions
Disaster Recovery
Business continuity plan (BCP)
BIA
Risk assessment
Continuity of operations
DRP
Recovery plans
Recovery sites
Replication and backup
Data replication
Synchronous and asynchronous
Replication methods
Data backup
Archive bit
Backup methods
Data versus OS restore
Backup media
Media storage
Backup media integrity
Backup media retention
Summary
Questions
Section 3: Security
Security Systems and Protocols
Security zones
Firewall zones
Demilitarized zone (DMZ)
Browser zones
Security devices
Authentication protocols
Authentication methods
Point-to-point authentication protocols
AAA authentication protocols
Secure Sockets Layer (SSL)/Transport Layer Security (TLS)
Internet Protocol Security (IPSec)
IPSec policies
IPSec modes
Port security
Port-based security
IEEE 802.1x
Access control list (ACL)
Router ACLs
Access list content
ACL types
Standard ACLs
Extended ACLs
Other ACL types
ACE types
Wildcard masks
Public key infrastructure (PKI)
PKI features
Encryption and authentication
Virtual private network (VPN)
Virtual LAN (VLAN)
Summary
Questions
Physical Security and Environmental Controls
MFA
Passwords
Authentication factors
General physical security concepts
Threats to physical security
Environmental threats
Man-made threats
Site-specific threats
Technical threats
Physical security devices
Environmental controls
Environmental monitoring
Electrical power
Uninterruptable Power Supplies (UPS)
UPS ratings
Automated shutdown of attached devices
Power distribution
PDU types
PDU ratings
Physical safety issues
Summary
Questions
Logical Security
Access control
Access control criteria
Access control levels
Filesystem access control
Access control to peripherals
Administration access control
Security and distribution groups
Network access control (NAC)
Data encryption
Storage encryption
Data retention and disposal
Erasing a disk
Formatting
Physically destroying a disk drive
Hardening
OS hardening
System hardening
Application hardening
Hardware hardening
Host hardware hardening
Network device hardening
Endpoint security
Summary
Questions
Section 4: Troubleshooting
Troubleshooting Methods
Troubleshooting steps
Identifying the problem
Hardware or software?
Hardware problems
Software problems
Establishing a probable cause
Define a plan of action
Verifying functionality
Documenting findings, actions, and outcomes
Summary
Questions
Common Hardware Issues
Hardware problems
Identifying a hardware problem
Common problems
POST failure
Overheating
Processor failure
Memory failure
Motherboard and component issues
Capacitor issues
Burns
USB not recognized
Expansion bus
PSUs
Hard Disk Drives (HDDs)
Video display
Other common problems
Environmental issues
Summary
Questions
Common Software Issues
Software problems
Hardware-related software problems
Common operating systems problems
Common problem causes
User Account Control (UAC)
Windows UAC
Access control
Corrupted files
Windows file recovery
Linux file recovery
Hard disk space problems
Lack of system resources
Virtual memory problems
Fragmentation
Printing issues
Log files
Operating system monitoring tools
Summary
Questions
Common Network Issues
Common network problems
Internet connectivity
Configurations
Dynamic Host Configuration Protocol (DHCP) server
APIPA
DHCP addresses
Other misconfigured devices
Email problems
Hosts file configuration
Misconfigured NIC
Routing and switching issues
VLAN configuration errors
Default gateway not available
Firewall failure
Miscellaneous common problems
Troubleshooting tools
ping
tracert/traceroute
ipconfig/ifconfig
nslookup
net use/mount
nbtstat and netstat
Summary
Questions
Common Storage Issues
Data storage device problems
Common HDD problems
Causes of common problems
Media failures
Hard disk media
SSD media
Magnetic tape media
Optical drives
Common storage problems causes
Drive and connector failures
HDD problems
Cable and connector problems
Storage system issues
Software-related failures
Hardware-related issues
Storage array issues
Administrative tools
Disk management
Disk partitioning tools
Map, mount, and net use
Disk arrays
RAID arrays
Storage monitoring tools
Summary
Questions
Common Security Issues
Common data security problems
Causes of common security problems
Security tools
Summary
Questions
CompTIA Server+ Examination
The exam
Registering for the Exam
Preparing for the exam
The certification
Glossary
0-9
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
Z
Assessment
Chapter 1: Server Hardware
Chapter 2: Server Internals
Chapter 3: Data Storage
Chapter 4:  Server Operating Systems
Chapter 5: Addressing
Chapter 6: Cabling
Chapter 7: Server Administration
Chapter 8: Server Maintenance
Chapter 9: Virtualization
Chapter 10: Disaster Recovery
Chapter 11: Security Systems and Protocols
Chapter 12: Physical Security and Environmental Controls
Chapter 13: Logical Security
Chapter 14: Troubleshooting Methods
Chapter 15: Common Hardware Issues
Chapter 16: Common Software Issues
Chapter 17: Common Network Issues
Chapter 18: Common Storage Issues
Chapter 19: Common Security Issues
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Preface
The CompTIA Server+ certification is one of the top five IT certifications that is vendor neutral. System administrators opt for the CompTIA Server + certification to gain advanced knowledge on concepts such as troubleshooting and networking. This book will start with the configuration of a basic network server and the configuration of each of its myriad roles. The next set of chapters will provide an overview of the responsibilities of and the tasks performed by a system administrator to manage and maintain a network server. Going ahead, you will learn about the basic security technologies, methods, and procedures that can be applied to a server and its network.
Next, you will cover troubleshooting procedures and methods in general, and specifically for hardware, software, networks, storage devices, and security applications. Towards the end of this book, you will cover a few troubleshooting and security mitigation concepts for running admin servers with ease. This guide is packed with test questions and mock papers, which will help you pass the exam.By the end of this book, you will be in a position to pass the CompTIA Server+ certification with ease.
Who this book is for
This book is targeted toward professionals seeking to gain the CompTIA Server+ certification. People from a Microsoft background with basic operating system and networking skills will also find this book useful. Basic experience of working with system administration is mandatory.
What this book covers
Chapter 1, Server Hardware, provides a review of the components that are likely to be found in a network server and gives enough detail to help an inexperienced reader understand the what and the why of server hardware. In the discussion of each of the functional server modes, its protocols, services, and purpose are also discussed. The chapter also looks at server power, cooling, and form factors.
Chapter 2, Server Internals, examines the components and systems inside the server's computer case to provide a brief overview of the purpose and function of each of them, as well as how they interact with other components.
Chapter 3, Data Storage, examines the devices and components that make up data storage systems that are common on networks. This chapter also discusses the various interfaces, technologies, and configurations of magnetic storage devices.
Chapter 4, Server Operating Systems, discusses the installation, configuration, and management of a network server operating system. Both Windows Server and Linux are covered. The chapter also takes a look at creating performance baselines and the configuration and administration of unattended or remote server installations.
Chapter 5, Addressing, provides a detailed look at IPv4 and IPv6 addressing, including discussions on CIDR, subnetworking, DNS, MAC, and FQDN. This chapter also includes information on network interfaces and TCP/UDP protocols and ports.
Chapter 6, Cabling, provides information on copper and fiber-optic cabling systems, including their connectors, configurations, designations, and installation.
Chapter 7, Server Administration, covers the tools, components, tasks, processes and management responsibilities used or performed to administer and maintain a server.
Chapter 8, Server Maintenance, covers the duties and activities involved in maintaining a server. This includes change and patch application and management, performance monitoring, and preventive maintenance.
Chapter 9, Virtualization, covers the concepts, configuration, and operation of virtualization technology, including hypervisors, hardware compatibility, allocation of resources, and virtual devices.
Chapter 10, Disaster Recovery, reviews the definitions, methods, products, and applications involved in disaster recovery and business continuity planning and execution.
Chapter 11, Security Systems and Protocols, covers the systems, protocols, and encryption key methods applied to secure a server. This includes firewalls, authentications, PKI, and security zones.
Chapter 12, Physical Security and Environmental Controls, covers the concepts, technologies, and methods applied in physical security programs, including MFA, security devices, and practices. This chapter also includes a discussion of the various electrical power concepts and applications, safety procedures, and the elements of environmental control.
Chapter 13, Logical Security, covers the concepts, technologies, and applications used to define and apply security procedures through system administration. This chapter also discusses data encryption, data storage security, hardening, and endpoint security.
Chapter 14, Troubleshooting Methods, discusses the procedures that should be used in any troubleshooting activity.
Chapter 15, Common Hardware Issues, identifies common hardware issues and the processes or methods used to isolate hardware issues and their causes.
Chapter 16, Common Software Issues, identifies common software issues on a server, their causes, and the tools used to detect, prevent, and resolve them.
Chapter 17, Common Network Issues, identifies common network issues on networks, their causes, and the tools used to detect, prevent, and resolve them.
Chapter 18, Common Storage Issues, identifies common hardware and software issues associated with disk drive storage attached to a server or network, their causes, and the tools used to detect, prevent, and resolve them.
Chapter 19, Common Security Issues, identifies common hardware and software issues associated with server and network security, their causes, and the tools used to detect, prevent, and resolve them.
Appendix A, CompTIA Server+ Examination, in this section , this section will go through the basic pre-requisites to clear the exam.
Appendix B, Glossary, this section will walk-through the basic term and definitions that are used throughout the book.
Appendix C, Server+ Practice Exam, you can test your knowledge of concepts required for CompTIA's Server+ exam by visiting the following link: https://www.packtpub.com/sites/default/files/downloads/Server_plus_Practice_Exams.pdf.
To get the most out of this book
In this book, you need the following:
A PC with a working internet connection
Windows system, preferably Windows Server, but Windows 10 is okay. You need Administrator permissions as well.
A Linux system, an emulator running on Windows works too.
Download the color images
We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781789534818_ColorImages.pdf.
Conventions used
There are a number of text conventions used throughout this book.
CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "In this entry, 162.29.5.12 is the source IP address and 0.0.0.0 is the wildcard mask."
A block of code is set as follows:
11111111.11111111.11111111.11111111 (decimal 255.255.255.255)
Any command-line input or output is written as follows:
$ nslookup packt.com
Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "The message The service cannot be started, either because it is disabled or because it has no enabled devices associated with it indicates that one or more services, programs, or scripts has failed to start."
Get in touch
Feedback from our readers is always welcome.
General feedback: If you have questions about any aspect of this book, mention the book title in the subject of your message and email us at [email protected].
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Section 1: System Architecture
This part of the book covers the configuration of a basic network server and the configuration appropriate to each of its myriad roles. The chapters in this part discuss hardware, operating systems, data storage, network addressing, and cabling.
The following chapters are included in this section:
Chapter 1
, Server Hardware
Chapter 2
, Server Internals
Chapter 3
, Data Storage
Chapter 4
, Server Operating Systems
Chapter 5
,
Addressing
Chapter 6
, Cabling
Server Hardware
It's generally assumed that a computer network server, at least in the way we talk about it, is hardware first and software second. While it's easier to envision a computer as a network server, in fact, the server is a piece of software running on the computer. In its most strict definition, a server is anything that provides services to fulfill requests made to it. Therefore, someone who takes our order and brings us our meal in a restaurant is a server and, in the same way, software running on a computer that processes an SQL request on a database and returns the data to the requester is also a server. Regardless of the way you envision a server, for the sake of learning about servers, let's agree that a centralized computer running server software that provides services to a network is a server.
With that understanding, let's look at the various roles fulfilled by a computer network server and the hardware of a typical computer in the role of a server.
In this chapter, we will cover the following topics:
Server roles
Form factors
Server power systems
System heat
Server roles
The software running on a server defines the role of that server. In fact, a server can have two or more different roles at times; it depends on the software. The list of the different roles a server can fulfill is long, but for the purposes of the Server+ exam, you should know the role and function of each of the following server types:
Application server
Database server
Directory server
File server
Mail server
Messaging server
Network services server
Print server
Routing and remote access server
Web server
The following sections explain each of these server roles.
Application servers
In the current environment of web-enabled or Software-as-a-Service (SaaS) applications in the cloud, an application server functions much like the generic description given above. An application server often provides services for one or more applications and serves as a mid-level service between user requests and other server- or network-based functions, such as a database system . There are three basic types of application servers. Their differences lie in what they do and where they fit into a process. The three types of application servers are as follows:
LAN application servers
: This type of application server can exist internally within an organization's local network and provide data-processing support to network users on one or more applications. They may host an entire application's processing or share the processing with a user's computer. A common implementation of this type of application server is a three-tier client/server environment in which the application server is middle-ware between a network user and a database management system. The following diagram illustrates a three-tier client/server system:
Query-based application servers
:
This type of application server hosts one or more scripting or programming language services used to request data from a database. A user's computer may have an active dashboard, a status board, or a specific scripting or service request system, such as
Active Server Page
(
ASP
),
JavaServer Pages
(
JSP
), Django, or Ruby on Rails. The application server accesses a database and returns current or real-time data back to the client software.
Application/web servers
: In many cases, application servers are becoming web servers and vice versa. Either type of server can support
Hypertext Transfer Protocol
(
HTTP
) request-and-response traffic and interact with client browsers. A stand alone web server (also called an HTTP server) typically includes several specialized scripts and database query services in addition to performing basic web server duties. A web-enabled application server includes the capability to deliver web content to a client's browser. Examples of web/application servers are IBM WebSphere, Oracle iPlanet, and Apache Tomcat, and Microsoft
Internet Information Services
(
IIS
).
Database servers
As shown in the preceding diagram, in the Application servers section, a database server provides an interface between client requests, either directly or through an application server, and a database management system and its database. In most cases, an application server passes data requests to the database server for the processing and retrieval of the requested data. The database server then returns the data back to the requesting node. In a database client/server environment, the database management system, which performs the input/output operations on the database, is the backend. The software running on a host computer or an application server is the frontend. Requests for data flow from the frontend to the backend and back again.
Directory servers
A directory server supports directory services. Okay, but what are directory services?Have you ever entered the lobby of a very tall building and used the directory board to locate where in the building the person or organization was that you needed to find? Typically, you'd find the name, which has the location on the same line. Sound familiar? Directory services cross-reference or map the names, designations, or locations of computer or network resources to their respective local or network addresses.
The resources identified and addressed typically include disk volumes, directories, folders, files, input devices, output devices, and any other devices attached or installed on a system. This service is essential in a network. With this information, a resource is located, used, and administered. Without directory services, network resource addressing would be like a town in which the houses don't have street addresses. Efficient network operations would be impossible. Directory services are also known as name services because they manage a namespace. A namespace is a data abstraction that holds a list of names or identities of system resources, in this case, and their network addresses or locations. The namespace allows users, applications, and other services to access resources without the need to know their locations in advance. A directory server, or name server, is a server application that provides the organization, management, and security of the directory or name services, for example, Microsoft Active Directory, Red Hat Directory Server, Lotus Domino.
File servers
A file server is just what its name suggests—a server for files. There are several different types of file servers, but in general, a file server provides data resources to other nodes on a network. The configuration of a file server is a combination of several factors, including storage capacity, access time, security, fault tolerance, and, of course, budget. To best serve the data needs of an organization, a file server must be set up with the right blend of these factors. File servers can serve one of two roles:
Dedicated file servers
: This type of file server expressly provides file or database content to clients. A dedicated file server serves in that capacity only.
Non-dedicated file servers
: This type of file server supports two or more server services or functions.
What defines each of these roles is the method used for data sharing. File servers can be a File Transfer Protocol (FTP) server, a Service Message Block/Common Internet File System (SMB/CIFS) protocol server, an HTTP server, or a Network File System (NFS) server. Another form of file server arrangement is a network-attached storage (NAS) system.
Mail servers
Mail servers, which are also known as email servers or mail transport agent (MTA), process and transport electronic mail messages for a network, up to and including the internet. A mail server emulates the functions of human postal workers in that it receives incoming mail and forwards it on to its destination, typically another mail server. The two primary protocols involved with mail servers and the delivery of emails are the Simple Message Transport Protocol (SMTP) and the Post Office Protocol 3 (POP3). SMTP transports messages between mail servers. POP3 is a client-based protocol that interacts with a mail server to send and receive messages addressed to a particular user.
Messaging servers
A messaging server is a middleware service that receives, forwards, or holds messages between client applications and services. These messages communicate requests, responses, and status updates between client processes running on a network. There are two primary types of messaging servers:
Point-to-point messaging servers
: This type of messaging is a communication between one client, through a messaging server, and a single addressee client. Although other clients may be monitoring the messaging channel, only the single client to which the message is addressed will receive the message. An example of a point-to-point messaging service is the Java message service.
Publish-subscribe messaging servers
: This type of messaging communicates a message from a client (the publisher), through the messaging server, to a messaging category that includes multiple subscribed clients. The subscribers indicate which message categories they wish to receive. The clients then receive messages from only the categories to which they have subscribed. An example of publish-subscribe messaging services are Faye, NATS, and Redis.
Network services servers
Network services are services provided by the network server to the network clients to provide core services, such as data storage input/output (I/O) operations, information display, peer-to-peer communication, and many others. A network service operates on the OSI application layer.
Although the network operating system (NOS) provides most network services, protocols, and services such as the Domain Name System (DNS), the Dynamic Host Configuration Protocol (DHCP), instant messaging, Voice over Internet Protocol (VoIP), Network Time Protocol (NTP), and email can run from a centralized network services server.
Print servers
A print server is a device (a computer, appliance, or software) that accepts print requests from clients and provides the sequencing and management of a network-attached printer, plotter, or other imaging device. A printer attached to a desktop computer directly can manage the print function through a print queue, typically on a first-come-first-served basis. On a network, with any number of clients requesting print services, access to a printer can be contentious at times. In addition to managing a network's print queue, a print server can also manage or enforce print policies, such as volume, color printing, and others. Today's print servers are stand-alone network devices dedicated to the single function of printing. The following diagram illustrates a wireless network that includes a print server:
Proxy server
Proxy servers are intermediate network services that accept network client requests for resources from remote servers. A proxy server examines a client's request and determines the most efficient way of providing the requested resource. Client requests can be for a service, a file, or a web page, among other network-based resources. In today's networks, proxy servers are web proxies that provide several functions, such as reducing network traffic, concealing a requester's identity, and, getting past IP address blocking. A proxy server doesn't necessarily require a centralized network computer to operate. A proxy server may be on one or more users' workstations, one server on a network, or at several points in between. The location of the proxy server isn't nearly as important as its capability to connect a user's workstation to the sought-after servers on the internet. There are several types of proxy servers, each of which provides a primary service. The most common types of proxy servers are:
Gateway proxy servers
: This type of proxy server, also known as
application-level gateways
or
tunneling proxy servers
, serve as portals between a local network and the internet, sending and receiving unchanged client requests and the resulting responses.
Internet-facing (forward) proxy servers
: This type of proxy server facilitate requests from their internal networks for resources from the internet.
Open proxy servers
: These are forward proxy servers that will send request-and-response messages to or from anywhere on an inter-network.
Internal-facing proxy servers
: This type of proxy server provides several ways to protect and service their internal networks. Reverse proxies can perform authentication, authorization, caching, decryption, and load balancing.
Reverse proxy servers
: A common use for internal-facing proxy servers is as reverse proxy servers. This type of proxy server accepts requests from the internet, such as HTTP requests, and passes them to the appropriate internal network server for processing.
Routing and Remote Access Service (RRAS)
RRAS is a Microsoft suite of protocols configured to provide three basic functions:
Firewall
: Windows Firewall in Windows Server 2008 replaced the basic firewall function in RRAS
Router
: The server configured to run RRAS can perform multi-protocol routing, including the routing of IP, IPX, AppleTalk,
Routing Information Protocol
(
RIP
),
Open Shortest Path First
(
OSPF
), and
Internet Group Management Protocol
(
IGMP
) messages
Remote access
: Provides remote access connectivity for dial-up and
virtual private network
(
VPN
) clients using AppleTalk, IP, or IPX
RRAS incorporates the use of Point-to-Point Protocol (PPP) as its transport protocol. This allows RRAS to combine the router and the remote access functions.
Virtual server
Anything virtual is like something, but it's not really it. So, a virtual server is like a server, without being one. Well, almost. A virtual server is a software-enabled logic object operating in the memory of a physical computer. A single physical computer can support several virtual servers, provided it has the hardware resources, primarily memory, to do so. As illustrated in the following diagram, a physical computer can support one, two, or even more virtual servers. In addition to the hardware and the appropriate device drivers, the virtualization layer, known as a hypervisor, provides direct support to the virtual servers, each of which occupies a shell in memory. Each virtual server can support numerous virtual machines, installed on the same host hardware or on other network computers:
Form factors
For computing hardware, a form factor designates the dimensions, shape, and other physical characteristics of a computer case and its contents, including the power supply, mountings for internal storage devices, the motherboard and its mountings, RAM, expansion cards, the socket for the microprocessor, and other slots and mountings. The image that follows shows a variety of motherboard form factors, each of which have been made to fit inside a computer case of the same form factor. An ATX motherboard mounts in an ATX computer case, for example:
Tower servers
It's common, especially in smaller networks and some home networks, to use a single tower computer as the network server. Tower computers, like the one shown in the following image, are inside a standing case or cabinet. Towers are commonly network servers. This means that a tower computer tends to have more different components and connectors than a Small Office/Home Office (SOHO) computer, even one in a tower case:
The upright and tall design of the tower case provides better cooling of the internal components. However, when tower computers are clustered, they take up more space and can create a complicated cabling arrangement. Plus, towers aren't the quietest computers around.
Rack mounts
The computer hardware on which a server runs fits into a slim chassis mounted in a rack system. The rack itself is typically either a two- or four-rail vertical structure. A server, or other rack-mounted device, attaches to the vertical rails using a rail kit, which consists of horizontally-mounted rails on which the device sits, and the fasteners to attach both to the vertical struts. The cabling that attaches to the rear of the rack-mounted device may install on a cable management arm, which helps to 1) organize the cabling on the device, and 2) allow the cabling to be out of the way when servicing or performing an upgrade on the unit. The height of a rack-mountable device is in rack units (U's). A rack unit is 1.75 inches (44.45 millimeters) tall. The size of a rack-mountable device is in the number of U's it will occupy in a vertical rack. The following diagram illustrates the relative sizes of a 1U, 2U, 3U, and a 4U half-rack mount. Servers are most commonly 1U or 2U in size:
The Electronics Industries Alliance (EIA) has established a standard for rack systems of 42U in height and either 19-inches or 23-inches wide (48.3 cm to 58.4 cm). The depth of the rack can vary with the size of the overall structure or cabinet, as illustrated in the following image:
Blade technology
A blade server enclosure houses server blades, each of which is a scaled-down computer that fits into a slot in the rack-mountable blade enclosure chassis. The aim of the blade's design is to reduce the physical size, the number of direct interfaces, and the overall power usage of the server system. To do this, each blade has the components required to perform its internal processing. The cooling, power, networking, cabling, and management systems are a part of the blade enclosure or supplied by other devices in the rack mount or cabinet. As shown in the following image, a blade server enclosure supports several server blades. Each of the server blades installed in the blade server is, in fact, a discrete server that has a processor, memory, network adapter, and a host bus adapter (HBA). It's common for a server blade to only support one application or service:
Server power systems
The power requirements of a server system, regardless of its form, are higher than needed by a desktop or laptop computer. Gilster's law (of everything computing) says:
This pretty much sums up the power and cooling systems for servers. The amount of power required by a server, measured in watts, is determined by the components installed and the devices attached to it. The same goes for cooling. The amount and kind of cooling required is a function of the heat generated by the components under power. However, whether the server is a stand alone computer or a blade server in a data center, the device power and cooling systems must provide a sufficient level of service to power and ventilate its components. The challenge in choosing and installing the right equipment for these tasks is anticipating growth in the systems or increased demand for these services. The de facto form factor standard for network servers is the standard-ATX (shown earlier, in the image published in the Form factors section). The ATX standard sets the form, fit, and function of a server's major components, primarily the motherboard, power supply unit (PSU), and case. This ensures that these components are compatible and interoperable.
Electrical power
Before we get too deep into electrical systems and electricity, let's establish the meanings of a few terms you'll find in the discussion:
Current
: The flow or movement of an electrical charge
Resistance
:
The properties of a wire that oppose the current flow
Amperes/Amps
: The rate of flow of an electrical current
Voltage
: The standard measure for the electrical force of a current
Watts
: The output rate of energy radiated, absorbed, or dissipated
Ground
: The protective measure with a conductive connection to the earth
These terms and their meanings are very important to a discussion on power supply and cooling systems. The following sections look at the different properties and applications of electrical power for a network server.
AC versus DC / 110V versus 230V
The primary function of a PSU is to convert an alternating current (AC) or a direct current (DC) into the low-voltage DC that powers the server's internal components. In North America, the predominant domestic electrical service is 120V AC (referred to as 110V), which has an actual range of 115V to 127V. The rest of the world (and some commercial data centers elsewhere, including the US) have a DC mains power standard of 230V, +/- 10%. In the US, the output voltage from a PSU conforms to the ATX standard of +3.3VDC, +5VDC, and +/- 12VDC, regardless of the electrical input. Because voltages can and do vary within a range, some systems use different numbers, although they designate similar systems. For example, the standard household voltage in the US is 120V AC. Notice that, in the following table, a 120V in the Wye voltage column can also supply 208V or 240V, depending on the circuit's connections:
Wye voltage
Delta voltage
120
208
120
240
230
400
240
415
277
480
347
600
Wye and delta
There are two standard configurations used in electrical circuit diagrams—wye and delta. These names describe the approximate shape each has in a circuit diagram. A wye configuration connects a current-bearing line to a neutral in a sort of Y pattern. A delta configuration connects two current-bearing lines together to create a triangular shape. The easy way to remember these is that a wye circuit uses a neutral and a delta circuit doesn't.
Negative 48V
The voltage standard in telecommunications signaling, including wireless networking, is negative 48V power. All electrical circuits operate with plus (positive) and minus (negative) polarities, which yields one live side and one ground side. The 110V and 230V systems connect the grounding connection to the negative (minus) side. Negative 48V power connects its ground to the positive (plus) side. In case you're wondering why telecom systems use a negative voltage standard, it's because this voltage is safer for humans, especially those climbing up telephone poles.
One phase versus three phases
Electrical circuits transmit in one of three configurations—single-phase, split-phase, or triple-phase. Here are basic definitions for these terms:
Single-phase power
: A two-wire distribution system for AC, in which one wire carries the electrical current and the other wire is the neutral. The following diagram illustrates the wave form of a single-phase line.
Split-phase power
: A three-wire single-phase distribution system for AC, in which two wires carry electrical current and the third wire is the neutral. Split-phase distribution is common to homes and small business buildings.
Three-phase power
: A four-wire system, in which three overlapping wires carry an AC current. Each wire, and its current, are offset from the other wires, as shown in the following diagram. The fourth wire serves as the neutral. Three-phase is the transmission standard for larger electrical grids, industrial use, and data centers:
PSU
Let's look at server power systems from the inside out, starting with the PSU mounted inside the server case. PSU modules are usually installed on the system case during manufacturing. However, because PSUs are the number one failure point in a computer system of any size, even those PSUs attached during manufacturing, are replaceable. The power needs of a server are dependent on its size and its installed or attached components. As the number of disk drives, network adapters, and RAM grows, the amount of electrical power a server needs also increases. A server's PSU needs to be more robust and operationally efficient than a standard PSU included in a typical desktop or portable computer. Because servers are essential to networks, they must be available, meaning that their power supply unit must continuously and consistently provide the voltage needed to power the server.
Wattage
Most of the power supplies available on the market, except those from the more reputable manufacturers, can have inferior components and claim overstated performance numbers. Although it is only one measure of a power supply's capabilities, many computer users rely on only the wattage rating of a PSU as the deciding factor for choosing one. Manufacturers understand that the wattage of a PSU is important to consumers, so they make sure it is very visible on the packaging and on the unit itself, as shown in the following image:
The 80-plus certification
The 80-plus program is a voluntary certification of computer PSUs based on their electrical efficiency. The 80 represents the quality threshold set as a minimum standard for operating efficiency at various load levels. Six levels of certification are available, based on the level of the unit's performance. Products that meet the requirements of each of the certification levels can include a badge on their packaging, marketing, and product labels, as shown in the subsequent image. The first level is the basic 80-plus certification (called White), which verifies that a PSU is 80 percent efficient under 20, 50, and 100 percent loads. The mid-level is Gold, which certifies units as having at least 87 percent efficiency at the three loads. The highest level is Titanium which verifies a unit with efficiencies above 90 percent under all load levels. This following image shows the various certifications of the 80-plus program:
Selecting the right PSU
There are several factors that you should consider when selecting a power supply for a server, beyond how much wattage you need. The following lists the characteristics and capabilities that you should consider when selecting the PSU that's right for your server:
Wattage
: This number represents the power demands the server will make of the PSU as measured in watts. There are several wattage calculators on the web (see the following screenshot) that you can use to determine the total wattage your server needs. It's recommended that you add the wattage for any planned server or network expansions in your initial calculations:
Connectors and modularity
: Make sure that the connectors provided with the PSU are compatible with the components that are to be attached and interconnected with it. A modular PSU has no built-in cables, only receptacles. This minimizes the amount of cabling on the PSU to only those that are necessary, which reduces clutter. Non-modular PSUs have different numbers and types of standard connectors. The connectors common to most current PSUs are:
ATX 24-pin or ATX 20+4-pin main power cable connector
8-pin
entry-level power supply
(
EPS
) +12 volt
4+4-pin +12 volt power cable connector
6-pin
PCI express
(
PCIe
)
8-pin PCIe
6+2-pin PCIe power cable connector
4-pin peripheral power cable connector
SATA power cable connector
High-efficiency rating
: The 80-plus certification is an excellent guideline, but you should verify a PSU's efficiency rating as having been set from testing under actual load simulation. An 80% rating means that 20% of a PSU's energy (wattage) escapes as heat.
Rails
: In the context of a PSU, a rail is an output current of a single voltage. For example, an ATX PSU has one 3.3V rail, two for 5V (one each for +/- 5V), two for 12V (one each for +/- 12V), and a 5V standby rail.
External connection
: It may sound trivial, but without an external power cable with the appropriate connectors for your location (country), all your careful planning and selecting will have been for nothing. If you are in the US, use a
National Electrical Manufacturers Association
(
NEMA
) standards power cord and plugs. NEMA 5-15P connectors are the most commonplace in the US. In situations such as data centers with higher power ratings, a more robust connection can be wise. In these situations, a twist-lock connector such as the NEMA 5-30R locks the plug head into the electrical outlet.
Voltage switching
: Many PSUs include a voltage sensor that automatically detects the electrical current and switches to its voltage and mode. However, not all PSUs have this capability—some have a manual switch, and some have no switch at all and support only a single electrical service.
Redundancy
One way to ensure that a server or server cluster is fault-tolerant and provides high availability is to incorporate a redundant power supply system. Redundant power systems provide a safety net should the active power supply fail. In its most basic form, a redundant power supply has two separate PSUs that can provide power to the server together, alternatively, or with one PSU active and the other in standby mode. The image in this section shows a four-unit redundant power supply. The transition between the redundant units uses one of three configurations:
OR
: OR is a mathematical process that chooses between two (or more) options, as in
either or
. In this configuration, two PSUs can either share the power-load duties or one of the PSUs can be in standby mode. In either case, when a
metal-oxide-semiconductor field-effect transistor
(
MOSFET
) senses a drop in the power output of a unit, it switches to the standby PSU.
N+1
: The N+1 switch-over method is common for redundant systems that have three or more power supplies. In this arrangement, the +1 PSU is the standby unit and the N units share the power conversion operation.
OR of N+1
: This method is common to PSU blade systems. Each blade is a part of an N+1 grouping and interconnected to two or more power buses. Like the other redundancy configurations, each N+1 grouping can share power conversion or be in standby mode:
System heat
All electronic devices produce heat. Some do so more than others, and cooling must reduce the heat effect to avoid failure or intermittent problems. The electronic components found inside a server (mostly on the motherboard) that produce significant heat include microprocessors, graphics processing units (GPUs), chipsets, RAM, and voltage regulator modules (VRMs). Of these, microprocessors (CPUs) and GPUs produce most of the heat inside a server. High heat conditions or a condition called thermal stress can affect the service life or operations of electronic components. Physics tells us that when things get hot, they expand, and when they cool off, they contract. Any electronic component that continuously goes through heat and cool cycles, meaning expansion and contraction, is stressed, which can lead to performance issues. The bigger the difference between how hot hot is and how cool cool is relates directly to the severity of the damage done. Most newer computer systems and processors now carry a rating called thermal design power (TDP), which represents the amount of heat produced by the system or unit. The following table lists a few examples of the maximum TDP rating of several processors. This value indicates the amount of heat the cooling system must dissipate to keep the system running as it should. Although there are no standards for interpreting TDP, a lower value indicates the power usage and the heat produced is lower. TDP is only a general indicator of a system's cooling needs.
Processor
Maximum TDP
Intel Atom Z3740
4W
AMD A10 Micro-6700T
5W
Intel Core i3-5020U
15W
Intel Xeon E5-2630L v4
55W
AMD Ryzen 5 PRO 2600
65W
Intel Core i5-7600K
91W
AMD Ryzen 7 2700X
105W
Intel Core i9-7980XE
165W
Cooling systems
Computers, regardless of shape, form, size, or application, require a cooling system. In desktops, towers, and some laptops, the cooling system is inside the case. For a blade server, the cooling may be in the blade cabinet, the rack cabinet, or in the computer room overall. Several different methods are available to cool the internal components of a computer system. Some of these systems are legacy and some are new. For the Server+ exam, you should understand the cooling systems described in the following sections.
Air cooling and air flow
A basic air-cooling system is typically a default system built into a computer's case and internal components. In its simplest form, an air-cooling system consists of a heat sink, thermal paste, and the computer's case fan. A heat sink attaches directly to a CPU with a small amount of thermal paste between the two to provide a thermal conductor. Air gaps between the heat sink and the CPU can act as thermal insulators, so the thermal paste eliminates this possibility. The heat sink is a ribbed metal extrusion that extends the surface of the CPU to allow more air to dissipate the heat. Air flow from one or more case fans moves across the fins of the heat sink to carry the heat away. This type of heat dissipation is known as passive cooling. Adding baffles, or air flow defectors, to passive cooling systems to specifically direct the air flow can enhance the effectiveness of the air-cooling system.
Some upper-end cases include not only multiple fans (two or more case fans and a graphics card fan), but a baffle system that directs the airflow to the CPU and other hots spots in the case. The alternative to cooling a computer with air flow is liquid cooling, which uses a coolant to pull the heat away from the CPU. Liquid cooling applies the thermodynamic principle that heat from a warm object will move to a cooler object. A CPU liquid cooling system works like the cooling system in an automobile. A liquid coolant, in this case distilled water, is pumped through an attachment on the CPU. The coolness of the water draws the heat of the CPU away and dissipates in the air flow.
The following image shows the radiator (on the left) and the CPU attachment (on the right):
