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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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– 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

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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 DevicesNetwork 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.

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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.

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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 IPv6Ex. IPv4 – 192.168.1.0 & IPv6 - 2001:db8:0:1234:0:567:1:1

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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

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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 PortsName Description Port

HTTP Hyper Text Transfer protocol 80

HTTPS Hyper Text Transfer protocol Secure 443

FTP File Transfer protocol 20, 21

SSH Secure Shell 22

Telnet Terminal port 23

DNS Domain Naming Server 53

DHCP Dynamic Host Configuration protocol 67, 68

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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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, MS-CHAP 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.

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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

– 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– 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