SlideShare ist ein Scribd-Unternehmen logo
1 von 28
Downloaden Sie, um offline zu lesen
System and network administration network services
Network services are the foundation of a
networked computing environment.
Generally network services are installed
on one or more servers to provide shared
resources to client computers.
 DNS
 DHCP
 FTP
 SMTP
 SNMP
 Proxy
 WWW
 Active Directory Services
A system for converting host names and domain
names into IP addresses on the Internet or on
local networks that use the TCP/IP protocol. For
example, when a Web site address is given to
the DNS either by typing a URL in a browser or
behind the scenes from one application to
another, DNS servers return the IP address of the
server associated with that name.
System and network administration network services
Because of the large volume of requests generated in the
DNS for the public Internet, the designers wished to
provide a mechanism to reduce the load on individual
DNS servers. To this end, the DNS resolution process allows
for caching of records for a period of time after an
answer. This entails the local recording and subsequent
consultation of the copy instead of initiating a new
request upstream. The time for which a resolver caches a
DNS response is determined by a value called the time to
live (TTL) associated with every record. The TTL is set by the
administrator of the DNS server handing out the
authoritative response.
The period of validity may vary from just seconds to days
or even weeks.
DNS was not originally designed with security in mind, and thus has a number of
security issues.
 One class of vulnerabilities is DNS cache poisoning, which tricks a DNS server into
believing it has received authentic information when, in reality, it has not.
 DNS responses are traditionally not cryptographically signed, leading to many
attack possibilities; The Domain Name System Security Extensions (DNSSEC)
modifies DNS to add support for cryptographically signed responses. There are
various extensions to support securing zone transfer information as well.
 Even with encryption, a DNS server could become compromised by a virus (or
for that matter a disgruntled employee) that would cause IP addresses of that
server to be redirected to a malicious address with a long TTL. This could have
far-reaching impact to potentially millions of Internet users if busy DNS servers
cache the bad IP data. This would require manual purging of all affected DNS
caches as required by the long TTL (up to 68 years).
 Some domain names can spoof other, similar-looking domain names. For
example, "paypal.com" and "paypa1.com" are different names, yet users may
be unable to tell the difference when the user's typeface (font) does not clearly
differentiate the letter l and the numeral 1
 Forward Zone
 Reverse Zone
 Local Zone/Local Host
(Dynamic Host Configuration Protocol)
A function in software that automatically
assigns temporary IP addresses to client
machines logging into an IP network.
Residing in the router or a server, DHCP
eliminates the need to manually assign
permanent "static" IP addresses to devices.
In a home network, the DHCP is typically in
the wireless router or wired router.
 dynamic allocation: A network administrator assigns a range of IP
addresses to DHCP, and each client computer on the LAN has its IP
software configured to request an IP address from the DHCP server
during network initialization. The request-and-grant process uses a lease
concept with a controllable time period, allowing the DHCP server to
reclaim (and then reallocate) IP addresses that are not renewed
(dynamic re-use of IP addresses).
 automatic allocation: The DHCP server permanently assigns a free IP
address to a requesting client from the range defined by the
administrator. This is like dynamic allocation, but the DHCP server keeps
a table of past IP address assignments, so that it can preferentially assign
to a client the same IP address that the client previously had.
 static allocation: The DHCP server allocates an IP address based on a
table with MAC address/IP address pairs, which are manually filled in
(perhaps by a network administrator). Only requesting clients with a
MAC address listed in this table will be allocated an IP address. This
feature (which is not supported by all devices) is variously called Static
DHCP Assignment).
 DHCP discovery
The client broadcasts messages (UDP) on the physical subnet to discover available DHCP servers
 DHCP offer
When a DHCP server receives an IP lease request from a client, it reserves an IP address for the client and
extends an IP lease offer by sending a DHCPOFFER message to the client. This message contains the client's
MAC address, the IP address that the server is offering, the subnet mask, the lease duration, and the IP
address of the DHCP server making the offer.
 DHCP request
A client can receive DHCP offers from multiple servers, but it will accept only one DHCP offer and broadcast a
DHCP request message. Based on the Transaction ID field in the request, servers are informed whose offer the
client has accepted. When other DHCP servers receive this message, they withdraw any offers that they might
have made to the client and return the offered address to the pool of available addresses. The DHCP request
message is broadcast, instead of being unicast to a particular DHCP server, because the DHCP client has still
not received an IP address.
 DHCP acknowledgement
When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters
its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client. This packet
includes the lease duration and any other configuration information that the client might have requested. At
this point, the IP configuration process is completed.
 DHCP releasing
The client sends a request to the DHCP server to release the DHCP information and the client deactivates its IP
address. As client devices usually do not know when users may unplug them from the network, the protocol
does not mandate the sending of DHCP Release.
File Transfer Protocol (FTP) is a standard network
protocol used to copy a file from one host to
another over a TCP/IP-based network, such as the
Internet. FTP is built on a client-server architecture
and utilizes separate control and data
connections between the client and server
applications, which solves the problem of
different end host configurations (i.e., Operating
System, file names).
FTP is used with user-based password
authentication or with anonymous user access.
 A client makes a connection to the server on TCP
port 21. This connection, called the control
connection, remains open for the duration of the
session.
 second connection, called the data connection, on
port 20 opened as required to transfer file data.
The control connection is used to send administrative
data (i.e., commands, identification, passwords).
Commands are sent by the client over the control
connection in ASCII and terminated by a carriage return
and line feed.
The standard e-mail protocol on the Internet
and part of the TCP/IP protocol suite.
SMTP defines the message format and the
message transfer agent (MTA), which stores
and forwards the mail. SMTP was originally
designed for only plain text (ASCII text), but
MIME and other encoding methods enable
executable programs and multimedia files to
be attached to and transported with the e-
mail message.
System and network administration network services
A widely used network monitoring and control
protocol. Data are passed from SNMP agents,
which are hardware and/or software processes
reporting activity in each network device (hub,
router, bridge, etc.) to the workstation console
used to oversee the network.
The agents return information contained in a MIB
(Management Information Base), which is a data
structure that defines what is obtainable from the
device and what can be controlled (turned off,
on, etc.). Originating in the Unix community, SNMP
has become widely used on all major platforms.
System and network administration network services
proxy server is a server (a computer system or an application
program) that acts as an intermediary for requests from clients
seeking resources from other servers. A client connects to the
proxy server, requesting some service, such as a file,
connection, web page, or other resource, available from a
different server. The proxy server evaluates the request
according to its filtering rules. For example, it may filter traffic
by IP address or protocol. If the request is validated by the
filter, the proxy provides the resource by connecting to the
relevant server and requesting the service on behalf of the
client. A proxy server may optionally alter the client's request
or the server's response, and sometimes it may serve the
request without contacting the specified server. In this case, it
'caches' responses from the remote server, and returns
subsequent requests for the same content directly.
A proxy server has a large variety of potential purposes,
including:
 To keep machines behind it anonymous (mainly for
security).
 To speed up access to resources (using caching). Web
proxies are commonly used to cache web pages from a
web server.
 To apply access policy to network services or content, e.g.
to block undesired sites.
 To log / audit usage, i.e. to provide company employee
Internet usage reporting.
 To bypass security/ parental controls.
 To scan transmitted content for malware before delivery.
 To scan outbound content, e.g., for data leak protection.
 To circumvent regional restrictions.
 Transparent and non-transparent proxy
server
 Suffix proxy
 Reverse proxy server
 Open proxy server
 Tunneling proxy server
 Content filter
 Web Proxy
The World Wide Web, abbreviated as WWW
and commonly known as the Web, is a
system of interlinked hypertext documents
accessed via the Internet. With a web
browser, one can view web pages that
may contain text, images, videos, and
other multimedia and navigate between
them by using hyperlinks.
A web hosting service is a type of Internet
hosting service that allows individuals and
organizations to make their own website
accessible via the World Wide Web. Web
hosts are companies that provide space on a
server they own or lease for use by their clients
as well as providing Internet connectivity,
typically in a data center.
Web hosts can also provide data center
space and connectivity to the Internet for
servers they do not own to be located in their
data center, called colocation.
 Virtual Hosting
Collection of several web sites on a single
web server.
 Virtually identified.
 An active directory is a directory structure used
on Microsoft Windows based computers and
servers to store information and data about
networks and domains. It is primarily used for
online information and was originally created
in 1996. It was first used with Windows 2000.
 An active directory (sometimes referred to as
an AD) does a variety of functions including
the ability to provide information on objects,
helps organize these objects for easy retrieval
and access, allows access by end users and
administrators and allows the administrator to
set security up for the directory.
 A Microsoft active directory, in simple terms, is like a giant
telephone book that organizes within it all of the
computers and people that have been entered into it. In
our case our active directory is called ADS (for Active
Directory Service). Unlike a telephone book however ADS
is not sorted alphabetically, but rather like the yellow
pages by category, in our case by department. This allows
us to mimic the universities administrative structure for
Academic Support departments.
 Administrators use an active directory to apply policies to
objects (computers and users), put people into security
groups (to allow and deny access to resources), and to
better keep track of things in groups (called
Organizational Units). Clients can make use of an active
directory to look up names, phone numbers and any
number of other attributes allowed by administrators.
 Objects
Everything that Active Directory tracks is considered an
object. An object is any user, system, computer, resource,
or service tracked within Active Directory. The generic
term object is used because Active Directory is capable of
tracking a variety of items, and many objects can share
common attributes.
 Sites
A Site object in Active Directory represents a geographic
location in that hosts networks. Sites contain objects called
subnets. Sites can be used to assign Group Policy Objects,
facilitate the discovery of resources, manage active
directory replication, and manage network link traffic.
 Forests, trees, and domains
A forest is a collection of Trees; Trees are a collection of
one or more Domains.
System and network administration network services
System and network administration network services
System and network administration network services

Weitere ähnliche Inhalte

Was ist angesagt?

introduction to system administration
introduction to system administrationintroduction to system administration
introduction to system administrationgamme123
 
IP tables and Filtering
IP tables and FilteringIP tables and Filtering
IP tables and FilteringAisha Talat
 
Chapter03 Creating And Managing User Accounts
Chapter03      Creating And  Managing  User  AccountsChapter03      Creating And  Managing  User  Accounts
Chapter03 Creating And Managing User AccountsRaja Waseem Akhtar
 
Presentation on samba server
Presentation on samba serverPresentation on samba server
Presentation on samba serverVeeral Bhateja
 
Duties of a system administrator
Duties of a system administratorDuties of a system administrator
Duties of a system administratorKhang-Ling Loh
 
Install and configure linux
Install and configure linuxInstall and configure linux
Install and configure linuxVicent Selfa
 
Network servers
Network serversNetwork servers
Network serversOnline
 
User account (Windows)
User account (Windows)User account (Windows)
User account (Windows)Dev Dorse
 
Understanding the Windows Server Administration Fundamentals (Part-1)
Understanding the Windows Server Administration Fundamentals (Part-1)Understanding the Windows Server Administration Fundamentals (Part-1)
Understanding the Windows Server Administration Fundamentals (Part-1)Tuan Yang
 
Subnetting Presentation
Subnetting PresentationSubnetting Presentation
Subnetting PresentationTouhidul Fahim
 
Information Security Lecture Notes
Information Security Lecture NotesInformation Security Lecture Notes
Information Security Lecture NotesFellowBuddy.com
 
What is a Server
What is a ServerWhat is a Server
What is a ServerKuwait10
 
Linux security introduction
Linux security introduction Linux security introduction
Linux security introduction Mohamed Gad
 
Introduction to computer network
Introduction to computer networkIntroduction to computer network
Introduction to computer networkAshita Agrawal
 

Was ist angesagt? (20)

introduction to system administration
introduction to system administrationintroduction to system administration
introduction to system administration
 
IP tables and Filtering
IP tables and FilteringIP tables and Filtering
IP tables and Filtering
 
IT system and network administrator
IT system and network administratorIT system and network administrator
IT system and network administrator
 
Chapter03 Creating And Managing User Accounts
Chapter03      Creating And  Managing  User  AccountsChapter03      Creating And  Managing  User  Accounts
Chapter03 Creating And Managing User Accounts
 
Presentation on samba server
Presentation on samba serverPresentation on samba server
Presentation on samba server
 
Samba server
Samba serverSamba server
Samba server
 
Duties of a system administrator
Duties of a system administratorDuties of a system administrator
Duties of a system administrator
 
Install and configure linux
Install and configure linuxInstall and configure linux
Install and configure linux
 
Network servers
Network serversNetwork servers
Network servers
 
User account (Windows)
User account (Windows)User account (Windows)
User account (Windows)
 
Understanding the Windows Server Administration Fundamentals (Part-1)
Understanding the Windows Server Administration Fundamentals (Part-1)Understanding the Windows Server Administration Fundamentals (Part-1)
Understanding the Windows Server Administration Fundamentals (Part-1)
 
DNS (Domain Name System)
DNS (Domain Name System)DNS (Domain Name System)
DNS (Domain Name System)
 
Ip address
Ip addressIp address
Ip address
 
Subnetting Presentation
Subnetting PresentationSubnetting Presentation
Subnetting Presentation
 
Client Server Architecture ppt
Client Server Architecture pptClient Server Architecture ppt
Client Server Architecture ppt
 
Information Security Lecture Notes
Information Security Lecture NotesInformation Security Lecture Notes
Information Security Lecture Notes
 
Basic Server PPT (THDC)
Basic Server PPT (THDC)Basic Server PPT (THDC)
Basic Server PPT (THDC)
 
What is a Server
What is a ServerWhat is a Server
What is a Server
 
Linux security introduction
Linux security introduction Linux security introduction
Linux security introduction
 
Introduction to computer network
Introduction to computer networkIntroduction to computer network
Introduction to computer network
 

Andere mochten auch

Network Administrator
Network AdministratorNetwork Administrator
Network Administratorguest371b1b4
 
Network ppt
Network pptNetwork ppt
Network ppthlalu861
 
Networking devices
Networking devicesNetworking devices
Networking devicesrupinderj
 
Basic concepts of computer Networking
Basic concepts of computer NetworkingBasic concepts of computer Networking
Basic concepts of computer NetworkingHj Habib
 
Computer networking devices
Computer networking devicesComputer networking devices
Computer networking devicesRajesh Sadhukha
 
BASIC CONCEPTS OF COMPUTER NETWORKS
BASIC CONCEPTS OF COMPUTER NETWORKS BASIC CONCEPTS OF COMPUTER NETWORKS
BASIC CONCEPTS OF COMPUTER NETWORKS Kak Yong
 

Andere mochten auch (10)

Network Administrator
Network AdministratorNetwork Administrator
Network Administrator
 
Common Network Services
Common Network ServicesCommon Network Services
Common Network Services
 
Network ppt
Network pptNetwork ppt
Network ppt
 
Networking devices
Networking devicesNetworking devices
Networking devices
 
Computer network ppt
Computer network pptComputer network ppt
Computer network ppt
 
Basic concepts of computer Networking
Basic concepts of computer NetworkingBasic concepts of computer Networking
Basic concepts of computer Networking
 
Computer networking devices
Computer networking devicesComputer networking devices
Computer networking devices
 
Networking
NetworkingNetworking
Networking
 
Networking ppt
Networking ppt Networking ppt
Networking ppt
 
BASIC CONCEPTS OF COMPUTER NETWORKS
BASIC CONCEPTS OF COMPUTER NETWORKS BASIC CONCEPTS OF COMPUTER NETWORKS
BASIC CONCEPTS OF COMPUTER NETWORKS
 

Ähnlich wie System and network administration network services

Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4
Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4
Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4Syed Ariful Islam Emon
 
dynamichost configuration protocol
dynamichost configuration protocoldynamichost configuration protocol
dynamichost configuration protocolrajisri2
 
Domain name system (dns) , TELNET ,FTP, TFTP
Domain name system (dns) , TELNET ,FTP, TFTPDomain name system (dns) , TELNET ,FTP, TFTP
Domain name system (dns) , TELNET ,FTP, TFTPsaurav kumar
 
DCHP,NAT,forwarding of ip packets
DCHP,NAT,forwarding of ip packetsDCHP,NAT,forwarding of ip packets
DCHP,NAT,forwarding of ip packetsrajshreemuthiah
 
A New Dynamic-Auto-Static Technique For DHCPv4 IP Address Allocation
A New Dynamic-Auto-Static Technique For DHCPv4 IP Address AllocationA New Dynamic-Auto-Static Technique For DHCPv4 IP Address Allocation
A New Dynamic-Auto-Static Technique For DHCPv4 IP Address AllocationStephen Faucher
 
Microsoft Exchange Technology Overview
Microsoft Exchange Technology OverviewMicrosoft Exchange Technology Overview
Microsoft Exchange Technology OverviewMike Pruett
 
DHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptx
DHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptxDHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptx
DHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptxMUHAMMADATTAURREHMAN7
 
Installation Of An Iso Image Dvd
Installation Of An Iso Image DvdInstallation Of An Iso Image Dvd
Installation Of An Iso Image DvdSusan Cox
 
Dynamic Host Configuration Protocol
Dynamic Host Configuration ProtocolDynamic Host Configuration Protocol
Dynamic Host Configuration ProtocolLauren Brown
 
06 coms 525 tcpip - dhcp and dns
06   coms 525 tcpip - dhcp and dns06   coms 525 tcpip - dhcp and dns
06 coms 525 tcpip - dhcp and dnsPalanivel Kuppusamy
 
Reply needed 1TCPIP is a networking protocol suite that Micros.docx
Reply  needed 1TCPIP is a networking protocol suite that Micros.docxReply  needed 1TCPIP is a networking protocol suite that Micros.docx
Reply needed 1TCPIP is a networking protocol suite that Micros.docxsodhi3
 
Content Navigation
Content NavigationContent Navigation
Content Navigationsanjoysanyal
 
Remote access service
Remote access serviceRemote access service
Remote access serviceApoorw Pandey
 

Ähnlich wie System and network administration network services (20)

Unit 6 : Application Layer
Unit 6 : Application LayerUnit 6 : Application Layer
Unit 6 : Application Layer
 
Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4
Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4
Ch2 the application layer protocols_ftp_telnet_samba_dhcp_4
 
Application layer protocols
Application layer protocolsApplication layer protocols
Application layer protocols
 
Network Testing ques
Network Testing quesNetwork Testing ques
Network Testing ques
 
DHCP
DHCPDHCP
DHCP
 
dynamichost configuration protocol
dynamichost configuration protocoldynamichost configuration protocol
dynamichost configuration protocol
 
Domain name system (dns) , TELNET ,FTP, TFTP
Domain name system (dns) , TELNET ,FTP, TFTPDomain name system (dns) , TELNET ,FTP, TFTP
Domain name system (dns) , TELNET ,FTP, TFTP
 
DCHP,NAT,forwarding of ip packets
DCHP,NAT,forwarding of ip packetsDCHP,NAT,forwarding of ip packets
DCHP,NAT,forwarding of ip packets
 
A New Dynamic-Auto-Static Technique For DHCPv4 IP Address Allocation
A New Dynamic-Auto-Static Technique For DHCPv4 IP Address AllocationA New Dynamic-Auto-Static Technique For DHCPv4 IP Address Allocation
A New Dynamic-Auto-Static Technique For DHCPv4 IP Address Allocation
 
Microsoft Exchange Technology Overview
Microsoft Exchange Technology OverviewMicrosoft Exchange Technology Overview
Microsoft Exchange Technology Overview
 
DHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptx
DHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptxDHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptx
DHCP DNS P1 DHCP & Wireless Communication Methods Unicasting.pptx
 
Lecture 14
Lecture 14Lecture 14
Lecture 14
 
Installation Of An Iso Image Dvd
Installation Of An Iso Image DvdInstallation Of An Iso Image Dvd
Installation Of An Iso Image Dvd
 
DHCP Server Guaidlines using CISCO PACKET TRACER
DHCP Server Guaidlines using CISCO PACKET TRACERDHCP Server Guaidlines using CISCO PACKET TRACER
DHCP Server Guaidlines using CISCO PACKET TRACER
 
Dynamic Host Configuration Protocol
Dynamic Host Configuration ProtocolDynamic Host Configuration Protocol
Dynamic Host Configuration Protocol
 
Internet
InternetInternet
Internet
 
06 coms 525 tcpip - dhcp and dns
06   coms 525 tcpip - dhcp and dns06   coms 525 tcpip - dhcp and dns
06 coms 525 tcpip - dhcp and dns
 
Reply needed 1TCPIP is a networking protocol suite that Micros.docx
Reply  needed 1TCPIP is a networking protocol suite that Micros.docxReply  needed 1TCPIP is a networking protocol suite that Micros.docx
Reply needed 1TCPIP is a networking protocol suite that Micros.docx
 
Content Navigation
Content NavigationContent Navigation
Content Navigation
 
Remote access service
Remote access serviceRemote access service
Remote access service
 

Mehr von Uc Man

Dhcp in linux
Dhcp in linuxDhcp in linux
Dhcp in linuxUc Man
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practiceUc Man
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practiceUc Man
 
Course outline pp_2
Course outline pp_2Course outline pp_2
Course outline pp_2Uc Man
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practiceUc Man
 
Course outline pp_2
Course outline pp_2Course outline pp_2
Course outline pp_2Uc Man
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practiceUc Man
 
Professionalism
ProfessionalismProfessionalism
ProfessionalismUc Man
 
Pro in the_workplace2
Pro in the_workplace2Pro in the_workplace2
Pro in the_workplace2Uc Man
 
Professional ethics in_computing
Professional ethics in_computingProfessional ethics in_computing
Professional ethics in_computingUc Man
 
Encryption & interception of communication
Encryption & interception of communicationEncryption & interception of communication
Encryption & interception of communicationUc Man
 
Effective time-management
Effective time-managementEffective time-management
Effective time-managementUc Man
 
Digital divide
Digital divideDigital divide
Digital divideUc Man
 
Course outline pp
Course outline ppCourse outline pp
Course outline ppUc Man
 
Computer crime
Computer crimeComputer crime
Computer crimeUc Man
 
Maintain yourself in professional practice
Maintain yourself in professional practiceMaintain yourself in professional practice
Maintain yourself in professional practiceUc Man
 
Time management
Time managementTime management
Time managementUc Man
 
Time management,planning and prioritization
Time management,planning and prioritizationTime management,planning and prioritization
Time management,planning and prioritizationUc Man
 
Student attendancereportofit 105(a)
Student attendancereportofit 105(a)Student attendancereportofit 105(a)
Student attendancereportofit 105(a)Uc Man
 
Privacy and personal information
Privacy and personal informationPrivacy and personal information
Privacy and personal informationUc Man
 

Mehr von Uc Man (20)

Dhcp in linux
Dhcp in linuxDhcp in linux
Dhcp in linux
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practice
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practice
 
Course outline pp_2
Course outline pp_2Course outline pp_2
Course outline pp_2
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practice
 
Course outline pp_2
Course outline pp_2Course outline pp_2
Course outline pp_2
 
Unit 3 maintain yourself in professional practice
Unit 3    maintain yourself in professional practiceUnit 3    maintain yourself in professional practice
Unit 3 maintain yourself in professional practice
 
Professionalism
ProfessionalismProfessionalism
Professionalism
 
Pro in the_workplace2
Pro in the_workplace2Pro in the_workplace2
Pro in the_workplace2
 
Professional ethics in_computing
Professional ethics in_computingProfessional ethics in_computing
Professional ethics in_computing
 
Encryption & interception of communication
Encryption & interception of communicationEncryption & interception of communication
Encryption & interception of communication
 
Effective time-management
Effective time-managementEffective time-management
Effective time-management
 
Digital divide
Digital divideDigital divide
Digital divide
 
Course outline pp
Course outline ppCourse outline pp
Course outline pp
 
Computer crime
Computer crimeComputer crime
Computer crime
 
Maintain yourself in professional practice
Maintain yourself in professional practiceMaintain yourself in professional practice
Maintain yourself in professional practice
 
Time management
Time managementTime management
Time management
 
Time management,planning and prioritization
Time management,planning and prioritizationTime management,planning and prioritization
Time management,planning and prioritization
 
Student attendancereportofit 105(a)
Student attendancereportofit 105(a)Student attendancereportofit 105(a)
Student attendancereportofit 105(a)
 
Privacy and personal information
Privacy and personal informationPrivacy and personal information
Privacy and personal information
 

Kürzlich hochgeladen

Lecture_6.pptx English speaking easyb to
Lecture_6.pptx English speaking easyb toLecture_6.pptx English speaking easyb to
Lecture_6.pptx English speaking easyb toumarfarooquejamali32
 
Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024Borderless Access
 
A flour, rice and Suji company in Jhang.
A flour, rice and Suji company in Jhang.A flour, rice and Suji company in Jhang.
A flour, rice and Suji company in Jhang.mcshagufta46
 
Mihir Menda - Member of Supervisory Board at RMZ
Mihir Menda - Member of Supervisory Board at RMZMihir Menda - Member of Supervisory Board at RMZ
Mihir Menda - Member of Supervisory Board at RMZKanakChauhan5
 
Slicing Work on Business Agility Meetup Berlin
Slicing Work on Business Agility Meetup BerlinSlicing Work on Business Agility Meetup Berlin
Slicing Work on Business Agility Meetup BerlinAnton Skornyakov
 
To Create Your Own Wig Online To Create Your Own Wig Online
To Create Your Own Wig Online  To Create Your Own Wig OnlineTo Create Your Own Wig Online  To Create Your Own Wig Online
To Create Your Own Wig Online To Create Your Own Wig Onlinelng ths
 
Cracking the ‘Business Process Outsourcing’ Code Main.pptx
Cracking the ‘Business Process Outsourcing’ Code Main.pptxCracking the ‘Business Process Outsourcing’ Code Main.pptx
Cracking the ‘Business Process Outsourcing’ Code Main.pptxWorkforce Group
 
Project Brief & Information Architecture Report
Project Brief & Information Architecture ReportProject Brief & Information Architecture Report
Project Brief & Information Architecture Reportamberjiles31
 
Chicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdf
Chicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdfChicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdf
Chicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdfSourav Sikder
 
MoneyBridge Pitch Deck - Investor Presentation
MoneyBridge Pitch Deck - Investor PresentationMoneyBridge Pitch Deck - Investor Presentation
MoneyBridge Pitch Deck - Investor Presentationbaron83
 
Building Your Personal Brand on LinkedIn - Expert Planet- 2024
 Building Your Personal Brand on LinkedIn - Expert Planet-  2024 Building Your Personal Brand on LinkedIn - Expert Planet-  2024
Building Your Personal Brand on LinkedIn - Expert Planet- 2024Stephan Koning
 
AMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdf
AMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdfAMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdf
AMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdfJohnCarloValencia4
 
PDT 89 - $1.4M - Seed - Plantee Innovations.pdf
PDT 89 - $1.4M - Seed - Plantee Innovations.pdfPDT 89 - $1.4M - Seed - Plantee Innovations.pdf
PDT 89 - $1.4M - Seed - Plantee Innovations.pdfHajeJanKamps
 
Borderless Access - Global B2B Panel book-unlock 2024
Borderless Access - Global B2B Panel book-unlock 2024Borderless Access - Global B2B Panel book-unlock 2024
Borderless Access - Global B2B Panel book-unlock 2024Borderless Access
 
NASA CoCEI Scaling Strategy - November 2023
NASA CoCEI Scaling Strategy - November 2023NASA CoCEI Scaling Strategy - November 2023
NASA CoCEI Scaling Strategy - November 2023Steve Rader
 
Team B Mind Map for Organizational Chg..
Team B Mind Map for Organizational Chg..Team B Mind Map for Organizational Chg..
Team B Mind Map for Organizational Chg..dlewis191
 
NewBase 25 March 2024 Energy News issue - 1710 by Khaled Al Awadi_compress...
NewBase  25 March  2024  Energy News issue - 1710 by Khaled Al Awadi_compress...NewBase  25 March  2024  Energy News issue - 1710 by Khaled Al Awadi_compress...
NewBase 25 March 2024 Energy News issue - 1710 by Khaled Al Awadi_compress...Khaled Al Awadi
 
7movierulz.uk
7movierulz.uk7movierulz.uk
7movierulz.ukaroemirsr
 
Anyhr.io | Presentation HR&Recruiting agency
Anyhr.io | Presentation HR&Recruiting agencyAnyhr.io | Presentation HR&Recruiting agency
Anyhr.io | Presentation HR&Recruiting agencyHanna Klim
 
Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024Borderless Access
 

Kürzlich hochgeladen (20)

Lecture_6.pptx English speaking easyb to
Lecture_6.pptx English speaking easyb toLecture_6.pptx English speaking easyb to
Lecture_6.pptx English speaking easyb to
 
Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024
 
A flour, rice and Suji company in Jhang.
A flour, rice and Suji company in Jhang.A flour, rice and Suji company in Jhang.
A flour, rice and Suji company in Jhang.
 
Mihir Menda - Member of Supervisory Board at RMZ
Mihir Menda - Member of Supervisory Board at RMZMihir Menda - Member of Supervisory Board at RMZ
Mihir Menda - Member of Supervisory Board at RMZ
 
Slicing Work on Business Agility Meetup Berlin
Slicing Work on Business Agility Meetup BerlinSlicing Work on Business Agility Meetup Berlin
Slicing Work on Business Agility Meetup Berlin
 
To Create Your Own Wig Online To Create Your Own Wig Online
To Create Your Own Wig Online  To Create Your Own Wig OnlineTo Create Your Own Wig Online  To Create Your Own Wig Online
To Create Your Own Wig Online To Create Your Own Wig Online
 
Cracking the ‘Business Process Outsourcing’ Code Main.pptx
Cracking the ‘Business Process Outsourcing’ Code Main.pptxCracking the ‘Business Process Outsourcing’ Code Main.pptx
Cracking the ‘Business Process Outsourcing’ Code Main.pptx
 
Project Brief & Information Architecture Report
Project Brief & Information Architecture ReportProject Brief & Information Architecture Report
Project Brief & Information Architecture Report
 
Chicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdf
Chicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdfChicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdf
Chicago Medical Malpractice Lawyer Chicago Medical Malpractice Lawyer.pdf
 
MoneyBridge Pitch Deck - Investor Presentation
MoneyBridge Pitch Deck - Investor PresentationMoneyBridge Pitch Deck - Investor Presentation
MoneyBridge Pitch Deck - Investor Presentation
 
Building Your Personal Brand on LinkedIn - Expert Planet- 2024
 Building Your Personal Brand on LinkedIn - Expert Planet-  2024 Building Your Personal Brand on LinkedIn - Expert Planet-  2024
Building Your Personal Brand on LinkedIn - Expert Planet- 2024
 
AMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdf
AMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdfAMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdf
AMAZON SELLER VIRTUAL ASSISTANT PRODUCT RESEARCH .pdf
 
PDT 89 - $1.4M - Seed - Plantee Innovations.pdf
PDT 89 - $1.4M - Seed - Plantee Innovations.pdfPDT 89 - $1.4M - Seed - Plantee Innovations.pdf
PDT 89 - $1.4M - Seed - Plantee Innovations.pdf
 
Borderless Access - Global B2B Panel book-unlock 2024
Borderless Access - Global B2B Panel book-unlock 2024Borderless Access - Global B2B Panel book-unlock 2024
Borderless Access - Global B2B Panel book-unlock 2024
 
NASA CoCEI Scaling Strategy - November 2023
NASA CoCEI Scaling Strategy - November 2023NASA CoCEI Scaling Strategy - November 2023
NASA CoCEI Scaling Strategy - November 2023
 
Team B Mind Map for Organizational Chg..
Team B Mind Map for Organizational Chg..Team B Mind Map for Organizational Chg..
Team B Mind Map for Organizational Chg..
 
NewBase 25 March 2024 Energy News issue - 1710 by Khaled Al Awadi_compress...
NewBase  25 March  2024  Energy News issue - 1710 by Khaled Al Awadi_compress...NewBase  25 March  2024  Energy News issue - 1710 by Khaled Al Awadi_compress...
NewBase 25 March 2024 Energy News issue - 1710 by Khaled Al Awadi_compress...
 
7movierulz.uk
7movierulz.uk7movierulz.uk
7movierulz.uk
 
Anyhr.io | Presentation HR&Recruiting agency
Anyhr.io | Presentation HR&Recruiting agencyAnyhr.io | Presentation HR&Recruiting agency
Anyhr.io | Presentation HR&Recruiting agency
 
Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024Borderless Access - Global Panel book-unlock 2024
Borderless Access - Global Panel book-unlock 2024
 

System and network administration network services

  • 2. Network services are the foundation of a networked computing environment. Generally network services are installed on one or more servers to provide shared resources to client computers.  DNS  DHCP  FTP  SMTP  SNMP  Proxy  WWW  Active Directory Services
  • 3. A system for converting host names and domain names into IP addresses on the Internet or on local networks that use the TCP/IP protocol. For example, when a Web site address is given to the DNS either by typing a URL in a browser or behind the scenes from one application to another, DNS servers return the IP address of the server associated with that name.
  • 5. Because of the large volume of requests generated in the DNS for the public Internet, the designers wished to provide a mechanism to reduce the load on individual DNS servers. To this end, the DNS resolution process allows for caching of records for a period of time after an answer. This entails the local recording and subsequent consultation of the copy instead of initiating a new request upstream. The time for which a resolver caches a DNS response is determined by a value called the time to live (TTL) associated with every record. The TTL is set by the administrator of the DNS server handing out the authoritative response. The period of validity may vary from just seconds to days or even weeks.
  • 6. DNS was not originally designed with security in mind, and thus has a number of security issues.  One class of vulnerabilities is DNS cache poisoning, which tricks a DNS server into believing it has received authentic information when, in reality, it has not.  DNS responses are traditionally not cryptographically signed, leading to many attack possibilities; The Domain Name System Security Extensions (DNSSEC) modifies DNS to add support for cryptographically signed responses. There are various extensions to support securing zone transfer information as well.  Even with encryption, a DNS server could become compromised by a virus (or for that matter a disgruntled employee) that would cause IP addresses of that server to be redirected to a malicious address with a long TTL. This could have far-reaching impact to potentially millions of Internet users if busy DNS servers cache the bad IP data. This would require manual purging of all affected DNS caches as required by the long TTL (up to 68 years).  Some domain names can spoof other, similar-looking domain names. For example, "paypal.com" and "paypa1.com" are different names, yet users may be unable to tell the difference when the user's typeface (font) does not clearly differentiate the letter l and the numeral 1
  • 7.  Forward Zone  Reverse Zone  Local Zone/Local Host
  • 8. (Dynamic Host Configuration Protocol) A function in software that automatically assigns temporary IP addresses to client machines logging into an IP network. Residing in the router or a server, DHCP eliminates the need to manually assign permanent "static" IP addresses to devices. In a home network, the DHCP is typically in the wireless router or wired router.
  • 9.  dynamic allocation: A network administrator assigns a range of IP addresses to DHCP, and each client computer on the LAN has its IP software configured to request an IP address from the DHCP server during network initialization. The request-and-grant process uses a lease concept with a controllable time period, allowing the DHCP server to reclaim (and then reallocate) IP addresses that are not renewed (dynamic re-use of IP addresses).  automatic allocation: The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator. This is like dynamic allocation, but the DHCP server keeps a table of past IP address assignments, so that it can preferentially assign to a client the same IP address that the client previously had.  static allocation: The DHCP server allocates an IP address based on a table with MAC address/IP address pairs, which are manually filled in (perhaps by a network administrator). Only requesting clients with a MAC address listed in this table will be allocated an IP address. This feature (which is not supported by all devices) is variously called Static DHCP Assignment).
  • 10.  DHCP discovery The client broadcasts messages (UDP) on the physical subnet to discover available DHCP servers  DHCP offer When a DHCP server receives an IP lease request from a client, it reserves an IP address for the client and extends an IP lease offer by sending a DHCPOFFER message to the client. This message contains the client's MAC address, the IP address that the server is offering, the subnet mask, the lease duration, and the IP address of the DHCP server making the offer.  DHCP request A client can receive DHCP offers from multiple servers, but it will accept only one DHCP offer and broadcast a DHCP request message. Based on the Transaction ID field in the request, servers are informed whose offer the client has accepted. When other DHCP servers receive this message, they withdraw any offers that they might have made to the client and return the offered address to the pool of available addresses. The DHCP request message is broadcast, instead of being unicast to a particular DHCP server, because the DHCP client has still not received an IP address.  DHCP acknowledgement When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client. This packet includes the lease duration and any other configuration information that the client might have requested. At this point, the IP configuration process is completed.  DHCP releasing The client sends a request to the DHCP server to release the DHCP information and the client deactivates its IP address. As client devices usually do not know when users may unplug them from the network, the protocol does not mandate the sending of DHCP Release.
  • 11. File Transfer Protocol (FTP) is a standard network protocol used to copy a file from one host to another over a TCP/IP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server applications, which solves the problem of different end host configurations (i.e., Operating System, file names). FTP is used with user-based password authentication or with anonymous user access.
  • 12.  A client makes a connection to the server on TCP port 21. This connection, called the control connection, remains open for the duration of the session.  second connection, called the data connection, on port 20 opened as required to transfer file data. The control connection is used to send administrative data (i.e., commands, identification, passwords). Commands are sent by the client over the control connection in ASCII and terminated by a carriage return and line feed.
  • 13. The standard e-mail protocol on the Internet and part of the TCP/IP protocol suite. SMTP defines the message format and the message transfer agent (MTA), which stores and forwards the mail. SMTP was originally designed for only plain text (ASCII text), but MIME and other encoding methods enable executable programs and multimedia files to be attached to and transported with the e- mail message.
  • 15. A widely used network monitoring and control protocol. Data are passed from SNMP agents, which are hardware and/or software processes reporting activity in each network device (hub, router, bridge, etc.) to the workstation console used to oversee the network. The agents return information contained in a MIB (Management Information Base), which is a data structure that defines what is obtainable from the device and what can be controlled (turned off, on, etc.). Originating in the Unix community, SNMP has become widely used on all major platforms.
  • 17. proxy server is a server (a computer system or an application program) that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource, available from a different server. The proxy server evaluates the request according to its filtering rules. For example, it may filter traffic by IP address or protocol. If the request is validated by the filter, the proxy provides the resource by connecting to the relevant server and requesting the service on behalf of the client. A proxy server may optionally alter the client's request or the server's response, and sometimes it may serve the request without contacting the specified server. In this case, it 'caches' responses from the remote server, and returns subsequent requests for the same content directly.
  • 18. A proxy server has a large variety of potential purposes, including:  To keep machines behind it anonymous (mainly for security).  To speed up access to resources (using caching). Web proxies are commonly used to cache web pages from a web server.  To apply access policy to network services or content, e.g. to block undesired sites.  To log / audit usage, i.e. to provide company employee Internet usage reporting.  To bypass security/ parental controls.  To scan transmitted content for malware before delivery.  To scan outbound content, e.g., for data leak protection.  To circumvent regional restrictions.
  • 19.  Transparent and non-transparent proxy server  Suffix proxy  Reverse proxy server  Open proxy server  Tunneling proxy server  Content filter  Web Proxy
  • 20. The World Wide Web, abbreviated as WWW and commonly known as the Web, is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia and navigate between them by using hyperlinks.
  • 21. A web hosting service is a type of Internet hosting service that allows individuals and organizations to make their own website accessible via the World Wide Web. Web hosts are companies that provide space on a server they own or lease for use by their clients as well as providing Internet connectivity, typically in a data center. Web hosts can also provide data center space and connectivity to the Internet for servers they do not own to be located in their data center, called colocation.
  • 22.  Virtual Hosting Collection of several web sites on a single web server.  Virtually identified.
  • 23.  An active directory is a directory structure used on Microsoft Windows based computers and servers to store information and data about networks and domains. It is primarily used for online information and was originally created in 1996. It was first used with Windows 2000.  An active directory (sometimes referred to as an AD) does a variety of functions including the ability to provide information on objects, helps organize these objects for easy retrieval and access, allows access by end users and administrators and allows the administrator to set security up for the directory.
  • 24.  A Microsoft active directory, in simple terms, is like a giant telephone book that organizes within it all of the computers and people that have been entered into it. In our case our active directory is called ADS (for Active Directory Service). Unlike a telephone book however ADS is not sorted alphabetically, but rather like the yellow pages by category, in our case by department. This allows us to mimic the universities administrative structure for Academic Support departments.  Administrators use an active directory to apply policies to objects (computers and users), put people into security groups (to allow and deny access to resources), and to better keep track of things in groups (called Organizational Units). Clients can make use of an active directory to look up names, phone numbers and any number of other attributes allowed by administrators.
  • 25.  Objects Everything that Active Directory tracks is considered an object. An object is any user, system, computer, resource, or service tracked within Active Directory. The generic term object is used because Active Directory is capable of tracking a variety of items, and many objects can share common attributes.  Sites A Site object in Active Directory represents a geographic location in that hosts networks. Sites contain objects called subnets. Sites can be used to assign Group Policy Objects, facilitate the discovery of resources, manage active directory replication, and manage network link traffic.  Forests, trees, and domains A forest is a collection of Trees; Trees are a collection of one or more Domains.