Chapter 2 Flashcards

(33 cards)

1
Q

What Is a Linux Server?

A
  • Linux desktops primarily focus on personal programs
  • The server runs programs that provide shared
    resources (called services) to multiple
    users (clients), normally in a network environment
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2
Q

Launching Services

A

■ As a background process, running at all times
listening for requests (daemons)
■ As a process spawned by a parent program that
listens for the requests (super-servers)

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3
Q

super-server program

A
  • internet daemon (inetd)

- extended internet daemon (xinetd)

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4
Q

Listening for Clients

  • The network protocol for a service defines exactly
    how network clients communicate with the service,
    using preassigned network ports.
  • Ports are defined within the TCP and UDP standards
A
  • Common Internet well-known port numbers:
Protocol      Port number
FTP                    20,21
SSH                      22
TELNET                23  
SMTP                    25  
DNS                      53
DHCP                    67 
HTTP                     80
POP                   109,110       
SMB                   137-139                 
IMAP                  143.220  
LDAP                     389      
HTTPS                   443     
NFS                       2049
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5
Q

Serving the Basics

A

The three Internet services:
■ Web services
■ Database services
■ Email services

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6
Q

Web Servers

A

The Apache Server
The nginX Server
The lighthttpd Package

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7
Q

The Apache Server

A
  • most popular web server on the Internet

- modularity

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8
Q

The nginX Server

A
  • web proxy, mail proxy, web page cache, and even
    load-balancing server
  • smaller memory
  • handling large traffic
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9
Q

The lighthttpd Package

A
  • low memory usage and low CPU usage

- built-in database

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10
Q

Database Servers

The Structured Query Language (SQL) provides a common method for clients to send requests to the database server and retrieve the data

A

open-source database servers:

  • The PostgreSQL Server
  • The MySQL Server
  • The MongoDB Server
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11
Q

The PostgreSQL Server

A
  • to rival the popular commercial database servers of
    the day.
  • PostgreSQL is very versatile, with versatility comes
    complexity
  • had a reputation for being somewhat slow
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12
Q

The MySQL Server

A
  • fast database system.
  • basic features
  • high-profile Internet web applications
  • LAMP platform
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13
Q

The MongoDB Server

A
  • object-oriented databases
  • NoSQL database doesn’t create tables but instead
    stores data as individual documents.
  • NoSQL document can contain different data elements
  • JavaScript Object Notation (JSON) elements
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14
Q

Mail Servers

A

■ The mail transfer agent (MTA) - on the Linux server
■ The mail delivery agent (MDA) - on the Linux server
■ The mail user agent (MUA) - end users,

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15
Q

The Mail Transfer Agent

A
  • handling both incoming and outgoing email
    messages on the server.
    ■ sendmail: very complex to configure correctly
    ■ Postfix: its simplicity. Instead of one large complex
    configuration file, Postfix uses just two small
    configuration files
    ■ Exim: one large program – avoid queuing messages
    – immediate delivery
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16
Q

The Mail Delivery Agent

A
  • concentrate only on delivering messages to local
    users
    ■ Binmail: simplicity
    ■ Procmail: versatility in creating user-configured
    recipes that allow a user to direct how the server
    processes received mail
17
Q

Serving Local Networks

A
  • File Servers

- Network Resource Servers

18
Q

File Servers

A

sharing files in a local network environment:
■ Peer-to-peer
■ Client/server
common server software packages
■ NFS : share folders in a network environment
- nfs-utils -
■ Samba : allow Linux systems to interact with
Windows clients and servers.
-System Message Block (SMB)-

19
Q

Print Servers

A

■ Common Unix Printing System (CUPS)

20
Q

Network Resource Servers

A
■ IP Addresses
■ Logging
■ Name Servers
■ Network Management
■ Time
21
Q

IP Addresses

A
  • Dynamic Host Confi guration Protocol (DHCP)
  • Linux DHCP server package: DHCPd
  • For Linux DHCP clients:
    ■ dhclient
    ■ dhcpcd
    ■ pump
22
Q

Logging

A

■ rsyslogd

■ journald

23
Q

Name Servers

A
  • Linux servers use the BIND software package to
    provide DNS naming services
  • main program in BIND is named
24
Q

Network Management

A
  • Simple Network Management Protocol (SNMP)
  • SNMPv1: simple password authentication
  • SNMPv2: basic level of security and bulk transmission
  • SNMPv3: strong authentication and data encryption
    capabilities as well as provides a more
    streamlined
    management system.
25
Time
- Network Time Protocol (NTP) | - ntpd
26
Implementing Security
- Authentication Server - Access Server (SSH) - Virtual Private Networks - Proxy Server - Monitoring
27
Authentication Server
- NIS : Network Information System (NIS)- nis-utils- Yellow Pages (YP). - Kerberos: symmetric-key- - LDAP: OpenLDAP package. hierarchical database
28
Certificate Authority
■ Something they possess, such as the certificate file | ■ Something they know, such as a PIN
29
Access Server (SSH)
- Secure Shell (SSH) provides a layer of encryption around data sent across the network. - OpenSSH package provides secure Telnet, FTP, and even remote copy features using SSH.
30
Virtual Private Networks
OpenVPN package
31
Proxy Server
Squid package
32
Monitoring
- Nagios: uses SNMP to monitor the performance and logs of Linux servers and provide results in a simple graphical window environment.
33
Improving Performance
- Clustering - Load Balancing - Containers