CISCO Chapter 3 Flashcards
Systems administrators do far more than manage servers; they are often called upon to assist users with _________ , _________ , and _________.
- configuration issues
- recommend new software
- update documentation among other tasks
Most Linux distributions allow users to download a “_________” installation package that can be loaded onto a USB key.
desktop
This is one of the first things aspiring system administrators should do
download a major distribution and load it onto an old PC
The Linux desktop should be familiar to anyone who has used a PC or Macintosh with icons to select different programs and a “settings” application to configure things like _________, _________, and _________
- user accounts
- WiFi networks
- input devices
After familiarizing oneself with the _________, or desktop, the next step is learning how to perform tasks from the command line.
Linux Graphical User Interface (GUI)
It is a simple text input system for entering anything from single-word commands to complicated scripts.Most operating systems have a _________ that provides a direct way of accessing and controlling the computer.
command line interface (CLI)
On systems that boot to a GUI, there are two common ways of accessing the command line:
- GUI-based terminal
- virtual terminal
is a program within the GUI environment that emulates a terminal window. It can be accessed through the menu system or search bar.
GUI terminal
Accessing the GUI terminal through the menu system.
click:
- Applications (menu bar)
- System tools
- Terminal
A _________ can be run at the same time as a GUI but requires the user to log in via the terminal before they can execute commands (as they would before accessing the GUI interface).
virtual terminal
Each Linux desktop distribution is slightly different, but the application terminal or _________ will open a terminal window from the GUI.
x-term
While there are subtle differences between the terms _________ and terminal window sessions, they are all the same from an administrators standpoint and require the same knowledge of commands to use
console
Ordinary _________ are starting programs, parsing scripts, and editing text files used for system or application configuration.
command line tasks
The _________ of the operating system is like an air traffic controller at an airport, and the applications are the airplanes under its control.
kernel
The _________ decides which program gets which blocks of memory, it starts and kills applications, and it handles displaying text or graphics on a monitor.
kernel
_________ make requests to the kernel and in return receive resources, such as memory, CPU, and disk space.
Applications
Applications make requests to the kernel and in return receive resources, such as _________, _________, and _________
- memory
- CPU
- disk space
If two applications request the same resource, the kernel decides which one gets it, and in some cases, _________ to save the rest of the system and prevent a crash.
kills off another application
The _________ also abstracts some complicated details away from the application. For example, the application doesn’t know if a block of disk storage is on a solid-state drive, a spinning metal hard disk, or even a network file share.
kernel
Applications need only follow the kernel’s _________ and therefore don’t have to worry about the implementation details.
Application Programming Interface (API)
Each_________ behaves as if it has a large block of memory on the system; the _________ maintains this illusion by remapping smaller blocks of memory, sharing blocks of memory with other applications, or even swapping out untouched blocks to disk
- application
* kernel
The kernel also handles the switching of applications, a process known as _________.
multitasking
A _________ has a small number of central processing units (CPUs) and a finite amount of memory.
computer system
The _________ takes care of unloading one task and loading a new one if there is more demand than resources available.
kernel
When one task has run for a specified amount of time, the _________ pauses it so that another may run.
CPU
a network service that talks to a remote computer
user-facing application
The kernel doesn’t differentiate between a _________ , a network service that talks to a remote computer, or an _________ .
- user-facing application
- internal task
A _________ is just one task that is loaded and tracked by the kernel.
process
note:
An application may even need multiple processes to function, so the kernel takes care of running the processes, starting and stopping them as requested, and handing out system resources.
The _________ can run a wide variety of software across many hardware platforms.
Linux kernel
A computer can act as a _________, which means it primarily handles data on others’ behalf
server
A computer can act as a _________, which means a user interacts with it directly.
desktop
The machine can run software or be used as a development machine in the process of creating _________.
software
A _________ can even adopt multiple roles as Linux makes no distinction; it’s merely a matter of configuring which applications run
machine
One resulting advantage is that _________can simulate almost all aspects of a production environment, from development to testing, to verification on scaled-down hardware, which saves costs and time.
Linux
A _________ could run the same server applications on a desktop or inexpensive virtual server that are run by large internet service providers
Linux administrator
Of course, a _________ would not be able to handle the same volume as a major provider would, but almost any configuration can be simulated without needing powerful hardware or server licensing.
desktop
Linux software generally falls into one of three categories:
- Server Applications
- Desktop Applications
- Tools
may not talk to other computers but only sit there and crunch data.
Server Applications
Software that has no direct interaction with the monitor and keyboard of the machine it runs on.
Server Applications
The Server Applications’ purpose is to serve information to other computers, called _________.
clients
are web browsers, text editors, music players, or other applications with which users interact directly.
Desktop Applications
A loose category of software that exists to make it easier to manage computer systems.
tools
it can help configure displays, provide a Linux shell that users type commands into, or even more sophisticated tools, called compilers, that convert source code to application programs that the computer can execute.
tools
that convert source code to application programs that the computer can execute.
compilers
is where the users type commands into
Linux shell
The _________ of applications varies depending on the distribution. Often application vendors choose a subset of distributions to support.
availability
Some applications, however, like _________ and _________ are widely supported and available for all major distributions.
- Firefox
- LibreOffice
_________ is an important skill to be learned by the aspiring Linux administrator. Determining requirements for performance, stability, and cost are just some of the considerations needed for a comprehensive analysis.
Evaluating application software
excels at running server applications because of its reliability and efficiency. The ability to optimize server operating systems with just needed components allows administrators to do more with less, a feature loved by startups and large enterprises alike.
Linux
A _________ hosts content for web pages, which are viewed by a web browser using the HyperText Transfer Protocol (HTTP) or its encrypted flavor, HTTPS.
web server
What is HTTP/HTTPS
HyperText Transfer Protocol / HyperText Transfer Protocol Secure
The web page itself can either be _________ or _________ .
- static
- dynamic
Users can develop content through their browser in the ________ application, and the software turns it into a fully functional dynamic website.
WordPress
is the dominant web server in use today.
Apache
Apache was originally a standalone project, but the group has since formed the ________ and maintains over a hundred open source software projects
Apache Software Foundation
is the daemon, or server application program, that “serves” web page requests.
Apache HTTPD
Another web server is ________, which is based out of Russia.
NGINX
It focuses on performance by making use of more modern UNIX kernels and only does a subset of what Apache can do.
NGINX
Over ________ of websites are powered by either NGINX or Apache.
65%
The ________ project was launched in 2010 by Frank Karlitschek to provide software to store, sync and share data from private cloud servers.
ownCloud
Who launched ownCloud project?
Frank Karlitschek
The ________ project was forked from ownCloud in 2016 by Karlitschek and has been growing steadily since then.
Nextcloud
2 private cloud servers:
- ownCloud
- Nextcloud
________ applications form the backbone of most online services.
Database server
________ applications pull data from and write data to these applications.
Dynamic web
a web program for tracking online students might consist of a front-end server that presents a web form. When data is entered into the form, it is written to a database application such as ________.
MariaDB
A ________ stores information and also allows for easy retrieval and querying
database
Example of popular databases:
- Firebird
- PostgreSQL
You might enter raw sales figures into the database and then use a language called ________ to aggregate sales by product and date to produce a report.
Structured Query Language (SQL)
When discussing email servers, it is always helpful to look at the 3 different tasks required to get email between people:
- Mail Transfer Agent (MTA)
- Mail Delivery Agent (MDA)
- POP/IMAP Server
software that is used to transfer electronic messages to other systems
Mail Transfer Agent (MTA)
The most well known Mail Transfer Agent MTA
Sendmail
is another popular one and aims to be simpler and more secure than Sendmail.
Postfix
Types of Mail Transfer Agent
- Sendmail
- Postfix
it takes care of storing the email in the user’s mailbox. Usually invoked from the final MTA in the chain.
Mail Delivery Agent (MDA)
Mail Delivery Agent (MDA) is also called?
Local Delivery Agent
are two communication protocols that let an email client running on your computer talk to a remote server to pick up the email.
POP/IMAP Server
POP means?
Post Office Protocol
IMAP means?
Internet Message Access Protocol
is a popular POP/IMAP server owing to its ease of use and low maintenance.
Dovecot
example of POP/IMAP servers:
- Dovecot
- Cyrus IMAP
People using standard file formats (such as all the emails in one text file) can choose any ________.
MDA
is shipped primarily as a software package/suite that includes all the necessary or approved components, all from Microsoft, so there are few if any options to make individual selections.
Microsoft Exchange
________ allows a Linux machine to look and behave like a Windows machine so that it can share files and participate in a Windows domain.
Samba
________ implements the server components, such as making files available for sharing and certain Windows server roles, and also the client end so that a Linux machine may consume a Windows file share.
Samba
The ________ project lets a Linux machine perform as an Apple Macintosh file server.
Netatalk
The native file sharing protocol for UNIX/Linux is called the ________
Network File System (NFS)
is usually part of the kernel which means that a remote file system can be mounted (made accessible) just like a regular disk, making file access transparent to other applications.
Network File System (NFS)
As a computer network becomes more substantial, the need for a directory increases. One of the oldest network directory systems is the ________
Domain Name System (DNS).
The ________ maintains the most popular DNS server, simply called bind after the name of the process that runs the service.
The Internet Software Consortium
The Internet Software Consortium maintains the most popular DNS server, simply called ________ after the name of the process that runs the service.
bind
The ________ is focused mainly on computer names and IP addresses and is not easily searchable. Other directories have sprung up to store information such as user accounts and security roles.
Domain Name System (DNS).
The ________ is one common directory system which also powers Microsoft’s Active Directory.
Lightweight Directory Access Protocol (LDAP)
In ________ , an object is stored in a tree, and the position of that object on the tree can be used to derive information about the object and what it stores.
Lightweight Directory Access Protocol (LDAP)
is the dominant program used in Linux infrastructure.
OpenLDAP
DHCP means?
Dynamic Host Configuration Protocol
LDAP means?
Lightweight Directory Access Protocol
DNS means?
Domain Name System
NFS means?
Network File System
MTA means?
Mail Transfer Agent
MDA means?
Mail Delivery Agent
it’s job is to listen for requests and to assign a free address from the DHCP pool.
Dynamic Host Configuration Protocol (DHCP)
is the most common open source DHCP server.
ISC DHCP server
The ________ has a wide variety of desktop applications. There are games, productivity applications, creative tools, web browsers, and more.
Linux ecosystem
The ________ came out with Thunderbird, a full-featured desktop email client.
Mozilla Foundation
it connects to a POP or IMAP server, displays email locally, and sends email through an external SMTP server.
Thunderbird
Other notable email clients are ________ and ________ which are the GNOME and KDE projects’ email clients.
- Evolution
- KMail
For the creative types, there is ________ , ________ , and ________ which handle 3D movie creation, 2D image manipulation, and audio editing respectively.
- Blender
- GIMP (GNU Image Manipulation Program)
- Audacity
is used for everything from independent films to Hollywood movies, for example.
Blender
supports high-quality photo manipulation, original artwork creation, graphic design elements, and is extensible through scripting in multiple languages.
GIMP (GNU Image Manipulation Program)
is a free and open source audio editing tool that is available on multiple operating systems.
Audacity
Use of common ________ in presentations and projects is one way to strengthen Linux skills.
open source applications
The basic productivity applications, such as a word processor, spreadsheet, and presentation package are valuable assets. Collectively they’re known as an ________, primarily due to Microsoft Office, the dominant player in the market.
office suite
Linux is a first class citizen for the ________ and ________ browsers. Both are open source web browsers that are fast, feature-rich, and have excellent support for web developers.
- Mozilla Firefox
- Google Chrome
Historically, the development of ________ shows considerable overlap between the skills of software development and systems administration.
UNIX
At the basic level, users interact with a Linux system through a ________ whether connecting to the system remotely or from an attached keyboard.
shell
it’s job is to accept commands, like file manipulations and starting applications, and to pass those to the Linux kernel for execution.
shell
The ____________ provides a rich language for iterating over files and customizing the environment, all without leaving the shell. For example, it is possible to write a single command line that finds files with contents matching a specific pattern, extracts useful information from the file, then copies the new information to a new file.
Linux shell
Linux offers a variety of shells to choose from, mostly differing in how and what can be customized, and the syntax of the built-in scripting language. The two main families are the ____________ and the ____________.
- Bourne shell
- C shell
The ____________ was named after its creator Stephen Bourne of Bell Labs.
Bourne shell
The____________ was so named because its syntax borrows heavily from the C language
C shell
As both these shells were invented in the 1970s, there are more modern versions, the ____________ and the ____________.
- Bourne Again Shell (Bash)
- tcsh (pronounced as tee-cee-shell)
is the default shell on most systems, though tcsh is also typically available.
Bourne Again Shell (Bash)
Programmers have taken favorite features from Bash and tcsh and made other shells, such as the _________ and the _________.
- Korn shell (ksh)
- Z shell (zsh)
Most Linux systems provide a choice of text editors which are commonly used at the console to edit configuration files. The two main applications are __________ and ________. Both are remarkably powerful tools to edit text files; they differ in the format of the commands and how plugins are written for them.
- Vi (or the more modern Vim)
- Emacs.
Most Linux systems provide a choice of __________ which are commonly used at the console to edit configuration files.
text editors
can be anything from syntax highlighting of software projects to integrated calendars.
Plugins
Both __________ and __________ are complex and have a steep learning curve, which is not helpful for simple editing of a small text file.
- Vi (or the more modern Vim)
- Emacs.
__________ and __________ are available on most systems and provide very basic text editing.
- Pico
- Nano
The __________ editor was developed as a completely open source editor that is loosely based on Pico
Nano
__________ is not an open source license and forbids making changes and distributing it.
Pico
While __________ is simple and easy to use, it doesn’t offer the extensive suite of more advanced editing and key binding features that an editor like Vi does.
Nano
Administrators should strive to gain some basic familiarity with __________, though, because it is available on almost every Linux system in existence
Vi
modern distributions use __________, which are compressed files that bundle up an application and its dependencies (or required files), greatly simplifying the installation by making the right directories, copying the proper files into them, and creating such needed items as symbolic links.
packages
A __________ takes care of keeping track of which files belong to which package and even downloading updates from repositories, typically a remote server sharing out the appropriate updates for a distribution.
package manager
In Linux, there are many different software package management systems, but the two most popular are those from __________ and __________.
- Debian
- Red Hat
The Debian distribution, and its derivatives such as Ubuntu and Mint, use the _____________.
Debian package management system
Derivatives of Debian distribution:
- Ubuntu
- Mint
At the heart of Debian package management are software packages that are distributed as files ending in the ________ extension
.deb
The lowest-level tool for managing these software packages that are distributed as files is the _________ command.
dpkg
The dpkg command can be tricky for novice Linux users, so the _________, apt-get (a front-end program to the dpkg tool), makes management of packages easier.
Advanced Package Tool
a front-end program to the dpkg tool
apt-get
Additional command line tools which serve as front-ends to dpkg include:
- aptitude
- GUI front-ends (like Synaptic and Software Center)
The _________ , which is a LINUX FOUNDATION project, is designed to specify (through a consensus) a set of standards that increase the compatibility between conforming Linux systems.
Linux Standards Base
According to the Linux Standards Base, the standard package management system is ________.
RPM
RPM makes use of an _________ file for each software package.
.rpm
This system (RPM) is what distributions derived from Red Hat, including _________ and _________, use to manage software.
- Centos
- Fedora
add-info:
Several other distributions that are not Red Hat derived, such as SUSE, OpenSUSE, and Arch, also use RPM.
ensures that when a package is installed, the system also installs any packages needed by that package to function correctly.
Tracking dependencies
also ensure that software updates and removals are performed properly.
Dependencies
The back-end tool most commonly used for RPM Package Management is the _________ command.
rpm
While the rpm command can install, update, query and remove packages, the command line front-end tools such as and automate the process of resolving dependency issues.
- yum
- up2date
A back-end program or application either interacts directly with a front-end program or is “called” by an _________ program.
intermediate
_________ programs would not interact directly with the user
Back-end
add-info:
there are programs that interact with people (front-end) and programs that interact with other programs (back-end).
There are also GUI-based front-end tools such as _________ and _________ that also make RPM package management easier.
- Yumex
- Gnome PackageKit
The _________ command is the basis of the ZYpp method, and it features short and long English commands to perform functions, such as zypper in packagename which installs a package including any needed dependencies.
zypper
Some RPM-based distributions have implemented the _________ package management style, mostly openSUSE and SUSE Linux Enterprise, but mobile distributions MeeGo, Tizen and Sailfish as well.
ZYpp (or libzypp)
provide a way for a programmer to enter instructions in a more human readable format, and for those instructions to eventually become translated into something the computer understands.
Computer programming languages
Programming languages fall into one of two camps:
- interpreted
- compiled
translates the written code into computer code as the program runs
interpreted language
- is code translated all at once.
compiled language
Linux itself was written in a compiled language called:
C
The main benefit of ________ is that the language itself maps closely to the generated machine code so that a skilled programmer can write code that is small and efficient.
C
Even with large memory sizes today, __________ is still helpful for writing code that must run fast, such as an operating system.
C
C has been extended over the years. There is __________ which adds object support to C (a different style of programming), and __________ that took another direction and is in heavy use in Apple products.
- C++,
- Objective C
In Java, instead of compiling to machine code, Java first imagines a hypothetical CPU called the __________ and then compiles all the code to that.
Java Virtual Machine (JVM)
add-info:
Each host computer then runs JVM software to translate the JVM instructions (called bytecode) into native instructions.
the __________ is relatively simple so it can be implemented quickly and reliably on anything from a powerful computer to a low power device that connects to a television.
JVM
are translated to machine code as they execute. The extra computer power spent doing this can often be recouped by the increased productivity the programmer gains by not having to stop working to compile.
Interpreted languages
also tend to offer more features than compiled languages, meaning that often less code is needed.
Interpreted languages
is usually written in another language such as C, and sometimes even Java! This means that an interpreted language is being run on the JVM, which is translated at runtime into actual machine code.
language interpreter
is a high-level interpreted programming language that is one of the core technologies on the world wide web.
JavaScript
JavaScript is similar to but fundamentally different from Java, which is a completely object-oriented programming language owned by Oracle
Oracle
is a cross-platform scripting language for adding interactive elements to web pages, that is in wide use across the internet.
JavaScript
is continuously evolving to meet the functionality and security needs of internet users and is capable of being released under a GNU GPL License.
JavaScript
refers to programing that abstracts complex actions and processes so that the end user only deals with basic tasks.
object-oriented
is an interpreted language. It was originally developed to perform text manipulation.
Perl
is a language that was initially built to create dynamic web pages. It’s file is read by a web server such as Apache.
PHP
The ________ pulls all the different parts of the file together and sends it to the web browser.
web server
main advantages are that it is easy to learn and available on almost any system.
PHP
many popular projects are built on PHP. Notable examples include:
- WordPress (for blogging)
- cacti (for monitoring)
- parts of Facebook
is another language that was influenced by Perl and Shell, along with many other languages. It makes complex programming tasks relatively easy, and with the inclusion of the it on Rails framework, is a popular choice for building complex web applications.
Ruby
is also the language that powers many of the leading automation tools like Chef and Puppet, which make managing a large number of Linux systems much simpler.
Ruby
is another scripting language that is in general use. Much like Ruby it makes complex tasks easier and has a framework called Django that makes building web applications very easy.
Python
has excellent statistical processing abilities and is a favorite in academia.
Python
is just a tool that makes it easier to tell the computer what you want it to do
computer programming language
is one such library that lets programmers manipulate images in code.
ImageMagick
also ships with some command line tools that enable programmers to process images from a shell and take advantage of the scripting capabilities there.
ImageMagick
is a cryptographic library that is used in everything from web servers to the command line. It provides a standard interface for adding cryptography into a Perl script
OpenSSL
provides a basic set of functions for reading and writing to files and displays, and is used by applications and other languages alike.
C library
are the primary mechanism that websites use to track you. Sometimes this tracking is good, such as to keep track of what is in your shopping cart or to keep you logged in when you return to the site.
Cookies
many sites have embedded scripts that come from third parties, such as a ________ or __________.
- banner advertisement
- Google analytics pixel
Tweaking ________ settings can make you more anonymous on the Internet, but it can also cause problems with some sites that depend on third-party cookies. If this happens, you might have to explicitly permit some cookies to be saved.
privacy
Browsers also offer a ________ where cookies and tracking pixels are deleted upon exiting the window. This mode can be helpful if you would like to search for something without letting other websites know what you are looking for.
private or incognito mode
The most privileged user on any Linux system is ________ ; this account is the primary ________ and is created when the operating system is installed.
- root
* administrator
Good ________ management is essential to security in any computing environment.
password
Increasingly users and administrators are turning to ________ programs to store login credentials in encrypted form.
password manager
a technique where a password is supplemented by a second “factor,” often a passcode sent to the user’s phone or other devices.
two-factor authentication (2FA)
Use a password manager like ________ to generate passwords, and then you only need to have a login password to your machine and a password to open up your ________ file.
KeePassX
is a device that filters network traffic, and Linux has one built-in.
firewall
If you are using Ubuntu, then the ________ is a graphical interface to Ubuntu’s Uncomplicated Firewall (UFW).
Gufw
is the built-in firewall system.
iptables
