Transcript Linux OS Concepts

Basic Networking and
Exchange Server
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Overview of Basic Networking
• Basics of Network, Types of Computer
Network, Components of computer Network
• OSI Model
• Network Connecting Devices
• IP Address
• Protocols
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Basic of Network
• Network definition
– A network is an interconnection of two
or more devices in order to enable
transfer of data or information from one
place to another
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Advantage and Disadvantage of
Network
• Advantages
– Sharing of Software and Hardware
resources
– Central storage and Data security
– Easier and faster sharing of information
• Disadvantages
– Costly Hardware and Software
– Need for an administrator to take care of
the network
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Types of Computer Network
Computer Networks:
• LAN
– A Network consisting of two or more computers
that are interconnected by means of cable in a
single location is called as Local Area Network.
• Types of LAN
–
Peer to Peer
• This is an example of simple network where two or more
computers are directly connected to each other and share
resources. There is no central control over the network.
Peer networks are organized into workgroups.
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Contd…
–
Server Based Network
• In this type of network, there is a main computer called
as the SERVER that controls the network and provides
central storage space for information. The other
computers that are connected to the Server are called as
CLIENTS, or WORKSTATIONS
–
Hybrid Network
• These types of network are a combination of both peer
to peer and SERVER network
Contd…
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• Wide Area Network
– A network of computers that are interconnected
over a large area is called Wide Area Network. The
computers are connected by means of Cables,
Telephone lines, Satellites or Radio transceivers.
i.e. Internet
• Metropolitan Area Network
– A network of computers that are interconnected
within a specific geographical area like university
campus or a city is called as Metropolitan Area
Network or Campus Area Network
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Network Connecting Devices
Network connecting devices are
•
•
•
•
•
•
–
Hubs
Switches
Routers
Ethernet Card
Cables & Connectors
Hubs
Hubs amplify signals and split them so that the signals reach their
destinations. Hubs available configurations are 4 /8/ 16/ 32 for
connection 4 /8/ 16/ 32 computers respectively. Hubs is isolated
device now.
Contd…
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• Switches
– These are the connecting points in a network where UTP and STP
cables are used. Switches amplify signals and split them so that the
signals reach their destination
– The main differences between hubs and switches is that hubs
transmit signals to all ports that are attached, whereas, switches
send the signal directly to the destination MAC address. Switches
also work in full-duplex mode where the signals can be transmitted
and received between the switch and the computer simultaneously
– Switches are available in configuration of 8/ 16/ 24/ 32 ports for
connecting computers
• Routers
– A Router is a combination of hardware and software. The hardware
may be a server or a separate routing device and the software
consists of the network operating system and the routing protocol.
Routers work at the network layer of the OSI model.
Contd…
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– Routers use the network address to select the appropriate
destination for signals.
– They are more intelligent than other devices because they have
special instructions to determine the quickest path to send a packet
to a network
– TCP/IP, NWLink, IPX are the popular routable protocols used in an
internetwork.
– RIPv1, RIPv2, OSPF, IGRP, EIGRP are the Network Operating
System protocols used to communicate from one place to another
place
• Ethernet Card
– An Ethernet card is one kind of network adapter. These adapters
support the Ethernet (Network) standard for high-speed network
connections via cables. Ethernet cards are sometimes called as
network interface card (NIC).
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Ethernet Cables and Connector
Category
Data Transfer
Speed
No. of Wires
Connector
Application
CAT 1
4MBPS
Two
RJ11
Voice Communication
CAT 2
4MBPS
Two
RJ11
Voice Communication
CAT 3
16MBPS
Four
RJ45
Computer Network
CAT 4
20MBPS
Four
RJ45
Computer Network
CAT 5
100MBPS
Four
RJ45
Computer Network
CAT 5e
1000MBPS
Four
RJ45
Computer Network
CAT 6
1GBPS
Four
RJ45
Computer Network
CAT 6e
10GBPS
Four
RJ45
Computer Network
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IP Address
• IP Address
– Internet Protocol (IP) address is a numerical identification and
logical address that is assigned to devices participating in a
computer utilizing the Internet Protocol for communication
between its nodes
– Two types of IP protocol versions are IPv4 and IPv6
Ex. IPv4 – 192.168.1.0 & IPv6 - 2001:db8:0:1234:0:567:1:1
Class
Start
End
Suffix
Default Subnet
A
0.0.0.0
127.255.255.255
/8
255.0.0.0
B
128.0.0.0
191.255.255.255
/16
255.255.0.0
C
192.0.0.0
223.255.255.255
/24
255.255.255.0
D
224.0.0.0
239.255.255.255
/4
Not defined
Contd…
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• Private IP Address
– Private IP addresses are typically used on local networks i.e.
home, school and business LANs including airports and
hotels.
– Devices with private IP addresses cannot connect directly to
the Internet.
– Computers outside the local network cannot connect directly
to a device with a private IP.
Class
Address Range
Subnet
Maximum Hosts
A
10.0.0.0 - 10.255.255.255
255.0.0.0
1,67,77,216
B
172.16.0.0 - 172.31.255.255
255.255.0.0
10,48,576
C
192.168.0.0 - 192.168.255.255
255.255.255.0
65,536
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Common Protocols and Ports
Name
Description
Port
HTTP
Hyper Text Transfer protocol
80
HTTPS
Hyper Text Transfer protocol Secure
443
FTP
File Transfer protocol
SSH
Secure Shell
22
Terminal port
23
Domain Naming Server
53
Telnet
DNS
20, 21
DHCP
Dynamic Host Configuration protocol
POP3
Post Office protocol
110
SMTP
Simple Mail Transfer protocol
25
LDAP
Light Weight Directory Access protocol
389
SNMP
Simple Network Management protocol
161, 162
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67, 68
DNS – Domain Name Server
• 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
DNS Possible Zones include:
– Forward lookup zone - Name to IP address map.
– Reverse lookup zone - IP address to name map.
– Standard primary zone (primary zone) - A master copy of a
forward or reverse lookup zone.
– Active Directory integrated zone - A copy of a standard primary or
Active Directory integrated zone. The IP address and computer
name is stored in Active Directory and replicated to all local domain
controllers. DNS information is not replicated to domain controllers
outside the domain.
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Common DNS Records
• AAAA Host resource record for IPv6 protocol
• A - Address record allowing a computer name to be translated
into an IP address. Each computer must have this record for its
IP address to be located. These names are not assigned for clients
that have dynamically assigned IP addresses, but are a must for
locating servers with static IP addresses.
• CNAME - Canonical name allowing additional names or aliases
to be used to locate a computer
• MX - Mail Exchange server record. There may be several
• MG - Mail group resource record.
• MINFO - Mailbox mail list information resource record
• ATMA - Asynchronous Transfer Mode resource record
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Authentication
• An authentication factor is a piece of information used
to authenticate or verify a person's identity on
appearance or in a procedure for security purposes
and with respect to individually granted access rights
• Authentication protocols are PAP, SPAP, CHAP, MSCHAP and EAP. NTLMV3, Kerberous
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Firewall
• A system designed to prevent unauthorized access to
or from a private network. Firewalls can be
implemented in both hardware and software, or a
combination of both. Firewalls are frequently used to
prevent unauthorized Internet users from accessing
private networks connected to the Internet, especially
intranets. All messages entering or leaving the intranet
pass through the firewall, which examines each
message and blocks those that do not meet the
specified security criteria.
Contd…
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• Firewall techniques:
– Packet filter: Looks at each packet entering or leaving the
network and accepts or rejects it based on user-defined rules.
Packet filtering is fairly effective and transparent to users, but
it is difficult to configure. In addition, it is susceptible to IP
spoofing.
– Application gateway: Applies security mechanisms to specific
applications, such as FTP and Telnet servers. This is very
effective, but can impose a performance degradation.
– Circuit-level gateway: Applies security mechanisms when a
TCP or UDP connection is established. Once the connection
has been made, packets can flow between the hosts without
further checking.
– Proxy server: intercepts all messages entering and leaving the
network. The proxy server effectively hides the true network
addresses.
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Proxy
• In computer networks, a proxy server is a server (a
computer system or an application program) that acts as
a go-between 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.
• Mainly Proxy server used for following purposes,
– To keep machines behind it anonymous (mainly for security).
– To speed up access to a resource (via caching). It is commonly used to
cache web pages from a web server or internet server.
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Microsoft Exchange Server
• Microsoft Exchange Server is a messaging and collaboration
server for integrated messaging and data storage.
– Exchange Server features include calendaring, contact
management, e-mail, and instant messaging.
– Exchange Server can store applications, documents, and Web
content and make them accessible via Internet protocols like HTTP
and NNTP
• Prerequisites to Install Exchange Server
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Active Directory Services
IIS – Internet Information Services
SMTP Service
Messaging Queuing Service
NNTP
DNS – Domain Name Server
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Microsoft Exchange Services
• Services are
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Microsoft Active directory connector
Microsoft Exchange event
Microsoft Exchange Imap4
Microsoft Exchange information store
Microsoft Exchange mta stack
Microsoft Exchange pop3
Microsoft Exchange smtp
Microsoft Exchange routing engine
Microsoft Exchange system attendant
Microsoft Exchange site replication services
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