Introduction : Server is a computer system that is shared by several users in network. A network consists of more than one computer, each each performing a particular task. An e-mail server receives and delivers e-mail over the network. A host (computer) in a network requires I.P address to communicate over the network. And I.P address is provided to the host by DHCP (Dynamic Host Configuration Protocol) it grant a temporarily I.P address to the clients not for some specified time. DNS (Domain Name System) provide name to I.P address mapping. It converts the computer name to an I.P address.WINS (Windows Internet Name Service) is another name resolution service that resolves windows networking computer name to an I.P address. NOS (Network Operating System) deals with concurrent requests from clients and provides the security necessary in a multi-user environment.
Client-server and Peer to Peer Network : In a client-server model,there can be only one server and one or more than one clients. the clients are connected to the server. This model consists of high end servers, which provides services to the clients as per the request sent by the client on a network. Client systems never function as servers. It is not possible for one client to access shared resources on another clients system. The Novel Netware is the example of this type of network operating system. Where clients are concerned, the on,y system on the network in the server system. The clients cannot see each other and they cannot share data with each other directly. It is necessary for the clients to save the data on the server so other systems can access it.
For example as shown in diagram that there is one server at the top of the network that means it head of the the network or Domain and also see that three are clients of this network means user all shown in the following diagram:
This Network is client server network .....
In a peer to peer network , computer on the network can have access to resources the data. The computers act as both clients and servers. The windows 9x series operating systems is one of the most common examples of peer to peer network. In this case , any system can act as a server or a client or both, depending on how we configure the network.
A peer to peer network in LAN consists of four computers connected as shown in figure below these computer can access the shared data such as audio, video or text and hardware resources such as Hard Disk Drive, CD-ROM for example a company XYZ has two terminals connected peer to peer network to store employs records. Hardware resources, such as a printer connected to one terminal can be used by other terminals with appropriate access rights.
Peer to Peer Network..
Access rights in peer to peer environment are regulated by configuring sharing permissions on the computer. For example, if a user needs to access a printer connected to the other computer in a peer to peer environment, the user needs to have appropriate rights to access to the printer. Access rights can be controlled by setting passwords.
Advantages and Disadvantages:
- Centralized management.
- Interoperability.
- Flexibility.
- Scalability.
- Accessibility.
Disadvantages:
- Expensive.
- Maintenance.
- Dependence.
- Security.
Types of Servers : The different servers can be used to perform different applications or roles. Depending on the nature of work, the servers can be classified into different types. The different types of server are:
- File Server = Used to store file which can be stored by clients connected in network. Clients can access part of hard disk of the server which will appear as an extra drive on their own computer. File server is also used to store applications which can be used by clients. The application can either run from the file server or can be downloaded to the client,s server system.
- Print Server = It controls all the printer requests sent from the other computers in the network . It routes the print request from clients to the printer. When a file is to be printed , the file is sent to be print server. The server is send file to the requested printer. Multiple user can share printer in network by using the print server.
- Mail Server = Used to send, receive and store mails over a network and across the Internet. The mail can be sent over LANs or WANs.
- Database Server = Provide data to network workstation. It is an application that is based on the client/server architecture.It is divided into two pars: ( i) Front -end application. ( ii)Back-end application.
- FTP Server = Used to download a file from the server or to upload a file to the server. It is a software application that runs the File Transfer Protocol (FTP) which is used for transferring bigger size files over the Internet.
- DNS Server = Used to translate domain name into I.P address. It also stores the information with domain names.
- DHCP Server = Used for assigning dynamic addresses to devices on a network.
- WINS Server = Allow a NetBIOS name to be converted to an I.P address.
E-Mail Server: E-Mail server is often referred to as mail server. A mail server is an application that receives e-mail from user on the local network. The e-mail server stores user lists, user rights and messages. An e-mail server maintains a storage area known as mailboxes for e-mails. Most E-Mail servers use Linux operating systems as they are less prone to viruses.
Domain Name System (DNS): Name resolution is the process of mapping computer names to their associated I.P addresses. The basic user enters in the browsers are converted into I.P addresses, so that the site can accessed. There are two ways to resolve name: NetBIOS, DNS
Network Basic Input/Output System (NetBIOS) uses flat name space. In the flate name space , two machines can,t share the same name. Flat name space works well on a small,isolated network. but not for a large organization with many interconnected networks as it is difficult to check that all the systems have a unique name. This drawback associated with the flat name space is overcome by hierarchical name space.
DNS uses hierarchical name space. DNS technique uses a distributed database. TCP/IP applications use the distributed database to map hostnames to the IP addresses to hostname case of reverse name resolution. Domain Name System is the technique used to provide naming conventions for finding IP address configured on hosts or computers. The Domain Name System is based on hierarchical and logical tree structure called Domain Namespace.
Name Resolution in DNS: If the IP address of the required site is known to you, the DNS is not required. But it is not an easy task to remember all the IP addresses of all the websites. So DNS is necessary to resolve the FQDN to IP address. It is necessary that,when you type a web address, Internet Explorer should resolve that name to the IP address of the web server to make connection to that web server. The name can be resolved in three ways; by broadcasting, by consulting a locally stored text file called HOSTS or by contacting a DNS server. Broadcast does not work across routers because routers do not forward broadcasts. Consulting a locally stored text file (HOSTS) - this file stores the names and addresses of machines on a network.
Network Operating Systems such as Windows NT, 2000 and 2003 Server, NetWare and Unix/Linux have built-in DNS server software.Dynamic Host Configuration Protocol (DHCP): This Protocol provides dynamic configuration of IP addresses. DHCP is mainly used for windows system. It provides all the information like IP address, default gateways, DNS address and so on. DHCP protocol is an extension to the Bootstrap protocol (BOOTP). BOOTP is a user datagram protocol used by the client on the network to obtain the IP address automatically. In a network a single system can get the IP information from the DHCP server, while other systems can use static IP information. DHCP reduces administration of a TCP/IP network.
By default DHCP server is available in netware, Linux and Windows NOS as well as most routers.
Server and Client Responsibilities: DHCP is also on the common TCP/IP model of client server operation. One computer plays the role of client and the other of a server. The client and the server have their set of responsibilities and must send and receive messages. DHCP makes both servers and clients exchange several types of message. The DHCP server and client play complementary roles. The server maintains configuration parameters for all clients and each client maintains its own parameters.
DHCP Server Responsibilities:-
- Address Storage and Management.
- Configuration Parameter Storage and Management.
- Lease Management.
- Responding To Client Requests.
- Providing Administration Servers.
DHCP Client Responsibilities:- Along the DHCP server, the DHCP client also has to carry out certain responsibilities. and they are as:
- Configuration Initiation.
- Configuration Parameter Management.
- Lease Management.
- Message Retransmission.
WINIPCFG and IPCONFIG commands are used to release and renew for an IP address. If you are changing to a new DHCP server, then first use release, and then renew command....
WINS: Windows Internet Name Services (WINS) map Network Basic Input/Output System (NetBIOS) computer names to the corresponding IP addresses. WINS was created by Microsoft to resolve the problems of broadcast-based name resolution. WINS server is used to reduce overhead from broadcasts and to allow NetBIOS name resolution across routers.
Similar to the DNS naming system, WINS is also use a hierarchical naming system. DNS depends on DNS servers, while WINS resolves through special WINS server software. A WINS Server maintains all the requests for NetBIOS names on a Windows TCP/IP network.
Computer registers first with the WINS server, when they log on to a WINS network. The server puts the client's NetBIOS name and IP address into its WINS database. any system on the network can query the WINS server for NetBIOS name resolution. A NetBIOS system claims a NetBIOS name for itself by broadcasting to the rest of the network. This only works as long as no other system is already using that name. In order to reduce the overhead of broadcasting by NetBIOS, Microsoft introduced a special text file called LMHOSTS. LMHOSTS contains a list of the IP addresses corresponding to the NetBIOS names of the host systems on the network. LMHOSTS file works exactly the same way as the DNS HOSTS file. NetBIOS in pure Windows environment.
WINS Troubleshooting : Most WINS problems are not directly related to WINS rather they are related to NetBIOS. the most common problem is two systems with the same name. In such situation, you receive an error message. To fix this error, change the name of the system.
NBTSTAT: NBTSTAT is used to troubleshoot NetBIOS name resolution problems. When a network is not working properly, NetBIOS over TCP/IP (NetBT) resolves NetBIOS names to IP addresses.
The nbtstat - a name
Sometimes it is confusing to remember about DNS, WINS, and DHCP is what each one does, i suggest some quick review to help you remember each one,s job.
- DNS - A TCP protocol that resolves domain names ( for example, http://www.smoketechnology.com/ ) into actual IP addresses.
- WINS - A Windows-only protocol used to resolved NetBIOS into IP addresses.
- DHCP - A protocol that automatically configures a system's IP information for nd users.
You may have noticed that DNS, WINS, and DHCP all require a server . Be careful with this terminology. In this context, server does not mean a physical computer -- it means a program that handles DNS ,DHCP, or WINS requests from client computers. Its fairly common, especially on smaller networks, for one server system to run all three of these server programs.
Windows 2000/XP/Vista/2003/2008 systems no longer need NetBIOS; they now use DNS, although they can support WINS if needed. Windows 9x and NT system, however, WINS to use NetBIOS name to connect within th work group.
Network operating System (NOS) : Network Operating System is an operating system for computer that can be connected to a network. A NOS applies protocols, device drivers and support for multiprocessing applications. NOS also supports internetworking features such as routing and WAN ports. WAN ports connects to cable or DSL modem to obtain an IP address from the cable modem or DSL modem. NOS organize the activities or multiple computers across a network. A file sharing component is installed in each client machine that interacts with the server to share files and applications as well as network devices such as printers, faxes and modems.
Microsoft, Novell, Apple and UNIX are main competitiors of Network Operating System.
Windows NT (New Technology) : Windows NT is similar to Windows 95 in terms of Graphical User Interface (GUI). Windows NT contains advanced features for security, network support, multitasking and user administration. Compared to Windows 95 and Windows 98, Windows NT was a very advanced operating system. Windows New Technology is basically a combination of two products; Windows NT Workstation and Windows NT Server.
* Windows NT Workstation:- Windows NT Workstation was especially developed for business users, who needed fast performance. Windows NT Workstation also included a version of Client Services for NetWare. This service supported Novell NetWare Directory Services (NDS), also known as eDirectory. eDirectory allowed Windows NT Workstation users to log on to Novell NetWare servers running NDS to access files and print resources.
*Windows NT Server:- Windows NT Servers was deaigned for machines with software applications that need to provide services to the network-attached computers. The NT server was the second most installed Network Operating System after Novell NetWare operating system. Microsoft NT server introduced a file directory approach called Active Directory that let the administrator and other users view every file and application in the network from a single point.
Windows 2000 : Windows 2000 is improved version of Windows NT. The desktop and a server version of winddows 2000 were Windows 2000 Professional and Windows 2000 server.
* Windows 2000 Professional:- Windows 2000 professional is the Windows operating system for business desktop computers and laptop. Windows 2000 Professional gives business user increased flexibility. It was built on Windows NT and had interface similiar to Windows 98 user interface.
*Windows 2000 server:- Windows 2000 Server differed from Windows 2000 Professional tools. Windows 2000 Server included all software necessary to run a Windows network including DNS, WINS and DHCP Server configuration.
*Active Directory:- A centralized storage area of information about network related to user, applications, files and printers is called Directory services. The applications in these services enabled the network administrators to centrally manage the network. Microsoft developed Windows 2000 as a Network Operating System with directory services. These services were called Active Directory. All the domain functions of Windows NT were incorporated into Active Directory. A single Active Directory consists of one or more domains.
Windows 2003 Server:- Windows 2003 is a .NET version of the Windows 2000 Server Operating System (O.S.). Windows 2003 Server was formally known as .NET Server 2003 .NET is the Microsoft Web Services used to connect different information, people, systems and devices through software. Web services are Web applications that interact with other Web applications for the purpose of exchanging data.
Windows Server 2003 is available in several editions:
- Small Business Server (Standard and premium Edition).
- web Edition.
- Standard Edition.
- Enterprise Edition.
- Datacenter Edition.
Features of Windows 2003 Server:
- Software and Hardware RAID.
- Distributed File System(DFS).
- Multi Path IO(MPIO).
- Virtual Disk Service.
Windows 2008 Server:- Microsoft Windows Server 2008 is the most advanced Windows Server Operating System yet, designed to power the next generation of networks, applications, and Web services. With Windows server 2008 we can develope, deliver, and manage rich user experiences and applications, provide a highly secure network infrastructure, and increase technological efficiency and value within your organization.
Windows XP Professional:- Windows XP is available in to editions; Windows XP Home Edition and Windows XP Professional Edition. Some features of Windows XP include device support and accessing remote desktop. Device support provides new and improved driver and user interface for devices compared to other version of Windows. Remote Desktop is used by Terminal Services and Wrb-based clients. Remote Desktop enables the user to connect to the Remote computer from another location. Share single Internet connection among multiple computers. As a computer system can be used by different users. Windows XP allows you to create a login for each user on that system. User can also share files among computers and a printer connected to a different computer in a local Area Network.
Windows XP install three network components by default:
- Client for Microsoft Network.
- File and Printer Sharing for Networks.
- TCP/IP protocol.
Windows Vista:- It's safer and more reliable and there are dozens of new features in Windows Vista.
Windows Vista includes built-in accessibieaslity settings and programs that make it easier for users to see, hear, and use their computers. The accessibility settings and programs in Vista are particularly helpful to people with visual difficulties, hearing loss, pain in their hands or arms,or reasoning conitive issues.
Major accessibility improvements in Windows Vista include:
- The new Ease of Access Center to help you find the settings and tool that make it easier for users to see, hear, and use your computer.
- Improved magnification capabilities in Microsoft Magnifier.
- Improved text-to-speech capabillities in Microsoft Narrator.
- The new Speech Recognition experience that lets you interact with your computer by voice.
Linux:- Linux is an open source computer operating system. Open source means that the source code for Linux is available to everyone. Linux is based on Unix operating systems was designed to support networking. Linux Operating System's means purpose was to offer free and very low-cost NOS to the Personal compuuter users. Linux O.S. is mainly used as a server. Linux supports TCP/IP networking, including FTP, Telnet and NFS. Linux supports various Network Adaptera and also file sharing with NFS and Nerware.
Novell Netware:- Novell Netware is a Local-Area Network operating system. Netware is a software product. Netware supports different types of LAN technologies from Ethernet to IBM's token-ring networks. Novell Netware uses packet-based protocol that enables Netware Core Protocol (NCP). Using NCP, a connection is established between the client and server. The basic working of NCP differs from other network protocols, which makes NCP more preferable. In other network protocols, when the client want to access data, the client sends a read request to the server, server acknowledges request. Client reveives acknowledgement. Server sends requested data to the client. Client acknowledges the data and the server accepts the acknowledgement. In NCP, all requests have associated sequence number. In case of requests already been processed, the server would resend the request with the sequence number.
THANK YOU
vikram singh
