Intranet@An intranet is a private network that is contained within an enterprise. It may consist of many interlinked local area networks and also use leased lines in the wide area network. Typically, an intranet includes connections through one or more gateway computers to the outside Internet. The main purpose of an intranet is to share company information and computing resources among employees. An intranet can also be used to facilitate working in groups and for teleconferences. @An intranet uses TCP/IP, HTTP, and other Internet protocols and in general looks like a private version of the Internet.How does intranet work?An Intranet can be defined as a private network which uses Internet tools. The principal tool is the Web browser, but there are other Internet tools such as ftp and telnet that are useful.For an Intranet to work, all computers connected together in a network must speak and understand the same language, or protocol. The language used is HyperText Mark-up Language (HTML) and the protocol that both Intranets and the Internet use are called Transmission Control Protocol/Internet Protocol or TCP/IP. A network server supports all the activities of an Intranet. On the clients’ side, a software, known as a browser, is used.

How is different from internetTo intranet?The Internet is an open, public space, while an intranet is designed to be a private space. An intranet may be accessible from the Internet, but as a rule it's protected by a password and accessible only to employees or other authorized users.Internet@Slow access speeds (e.g. 56Kbps dial up connectivity)@Different types of web browsers are used to view the website (e.g. Netscape, IE, Opera)@Different types of operating systems are used to view the website (e.g. Windows, Mac)@Global audience (e.g. multilingual, different cultures)

Intranets@Faster access speeds (e.g. 100Mbps LAN connectivity).@Standardized type of browser. Minimal or no compatibility issues@Standardized type of operating systems.@Primarily local audience

@Virtual Private Networks (VPN). A virtual private network (VPN) is a network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization's network. A virtual private network can be contrasted with an expensive system of owned or leased lines that can only be used by one organization. The goal of a VPN is to provide the organization with the same capabilities, but at a much lower cost.A VPN works by using the shared public infrastructure while maintaining privacy through security procedures and tunneling protocols such as the Layer Two Tunneling Protocol (L2TP). In effect, the protocols, by encrypting data at the sending end and decrypting it at the receiving end, send the data through a "tunnel" that cannot be "entered" by data that is not properly encrypted. An additional level of security involves encrypting not only the data, but also the originating and receiving network addresses.

Unshielded Twisted Pair (UTP) Cable@Twisted pair cabling comes in two varieties: shielded and unshielded. @Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. @The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. @The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot

Firewall@A system designed to prevent unauthorized

Advantages of Intranet@Intranets offering workforce productivity which can help user to find and observe information very fast. User may also use applications according to their roles and tasks. Through web browser a user can get access to entire contents of any website from anywhere or any time. @Intranet also increase the ability of employee’s by performing their job confidently very fast, and accurately.@ Intranet permits business companies to share out information to employees according to their need or requirements. Employees may also link to appropriate data at their expediency.@Intranet offering their user to write applications on their browser without cross-browser compatibility issues. @Intranet is a Web-based tool that permits users to produce a customized site according their requirements. You can pull all Internet actions and most wanted contented into a single page which make easier to access.@ Intranet providing cross platform capability for UNIX, Mac, Windows.@Through Intranet common corporate culture every user can view the similar information. @ Now intranet facilitates their user o view and gets information and data via web browser. Intranet also save the money of any organization on printing, publishing and overall maintenance Disadvantages of Intranet@Intranet has great features for interconnected manners but has some disadvantages too@Management does need to stop control of specific information, this problem can be minimized but with appropriate prudence. @The other disadvantage of Intranet is security issue@Intranet gathered everything in one location which is really good but if it is not prearranged then you will spoil everything. @The cost of intranet is very high but has lots of advantages after implementing. Multiple Layers of Intranet Security@Security requirements vary from one organization to the next, and among an organization's different kinds of content. For most intranets, more than a firewall is needed.  @Security is not just about access. It also protects information from accidental or willful alteration or destruction. Most security experts say a security breach is more likely to come from a company's own staff than from outside. @These may be disgruntled employees, or those who are after the thrill of breaking the code. Either way, this implies the highest risk is inside the firewall.  @In the physical world we have layers of security: A bank has vaults, locks, guards, and alarms, and each covers the weaknesses of the others. Intranets have a similar layered approach. At the center is server security, and content is only as secure as the server on which it is stored.  @Most commercial servers include a base level of operating-system and file-system security. Some servers require additional software to control access to server resources and files. These measures are like locks: Only those with keys can gain access. 

Types of intranet

Intranets classified into three type’sBulletin Board :- @This type of Intranet in an organization extends to everyone the capability to review or update information that would normally be placed on an organization Bulletin Board, such as, a calendar of events, a status board, pictures of events or employees, policy changes, etc.

Database Management:-This type of Intranet provides everyone in an organization with the capability to maintain a “real-time” interactive database. The database can be used to support the tracking of products, inventories, bidding, or provide information on a particular subject any time of day, from any location. Information Access :-This type of Intranet is the type commonly found on the World Wide Web. The static web page may include information on any subject. The static page can then be accessed from a simple search engine provided free as part of the Internet. Such “free service” networks are now-a-days making good money through advertisements

Client/serverA network architecture in which each computer or process on the network is either a client or a server. Servers are powerful computers or processes dedicated to managing disk drives (file servers), printers (print servers), or network traffic (network servers ). Clients are PCs or workstations on which users run applications. Clients rely on servers for resources, such as files, devices, and even processing power. Another type of network architecture is known as a peer-to-peer architecture because each node has equivalent responsibilities. Both client/server and peer-to-peer architectures are widely used, and each has unique advantages and disadvantages. Client-server architectures are sometimes called two-tier architectures.

Shielded Twisted Pair (STP) Cable@ If you must place cable in environments with lots of potential interference, or if you must place cable in extremely sensitive environments that may be susceptible to the electrical current in the UTP, shielded twisted pair may be the solution. Shielded cables can also help to extend the maximum distance of the cables.@ Shielded twisted pair cable is available in three different configurations:@Each pair of wires is individually shielded with foil.@There is a foil or braid shield inside the jacket covering all wires (as a group).@There is a shield around each individual pair, as well as around the entire group of wires (referred to as double shield twisted pair).

ThreatsIt must be clearly understood that the source of threat and the likely target could be many in number but all of them can be classified as either major or minor threats Similarly, they can be organized into two groups viz., internal or external threats. Details of threats have been dealt with in subsequent paragraphsInternal threats: Internal attacks originate from dissatisfied or unhappy inside employees or contractors. Internal attackers have some form of access to the system and usually try to hide their attack as a normal process. For instance, internal disgruntled employees have local access to some resources on the internal network already. They could also have some administrative rights on the network. One of the best means to protect against internal attacks is to implement an Intrusion Detection System, and to configure it to scan for both external and internal attacks. All forms of attacks should be logged and the logs should be reviewed and followed up.With respect to network attacks, the core components which should be included when you design network security are:

Network attack prevention. Network attack detection. Network attack isolation. Network attack recovery.

External threats: External threats or network attacks are carried out by individuals with no assistance from internal employees or contractors. These attacks are typically performed by a malicious experienced individual, a group of experienced individuals, an experienced malicious organization, or by inexperienced attackers (script kiddies). External threats are usually performed by using a predefined plan and the technologies (tools) or techniques of the attacker(s). One of the main characteristics of external threats is that it usually involves scanning and gathering information. You can therefore detect an external attack by scrutinizing existing firewall logs. You can also install an Intrusion Detection System to quickly identify external threats.External threats can be further categorized into either structured threats or unstructured threats:Web serversWeb servers are computers that deliver (serves up) Web pages. Every Web server has an IP address and possibly a domain name. For example, if you enter the URL http://www.pcwebopedia.com/indexhtml in your browser, this sends a request to the Web server whose domain name is pcwebopedia.com. The server then fetches the page named index.html and sends it to your browser Any computer can be turned into a Web server by installing server software and connecting the machine to the Internet. There are many Web server software applications, including public domain software from NCSA and Apache, and commercial packages from Microsoft, Netscape and others.

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.Types of Firewall ArchitecturesPacket filter firewallsIn a packet filtering firewall, data is forwarded based on a set of firewall rules. This firewall works at the network level. Packets are filtered by type, source address, destination address, and port information. These rules are similar to the routing rules explained in an earlier section and may be thought of as a set of instructions similar to a case statement or if statement. This type of firewall is fast, but cannot allow access to a particular user since there is no way to identify the user except by using the IP address of the user's computer, which may be an unreliable method. Also the user does not need to configure any software to use a packet filtering firewall such as setting a web browser to use a proxy for access to the web. The user may be unaware of the firewall. This means the firewall is transparent to the client.Proxy serversMost modern firewalls distinguish between packet filtering and proxy server services. A firewall proxy server is an application that acts as an intermediary between tow end systems. Firewall proxy servers operate at the application layer of the firewall, where both ends of a connection are forced to conduct the session through the proxy. They do this by creating and running a process on the firewall that mirrors a service as if it were running on the end host. A firewall proxy server essentially turns a two-party session into a four-party session, with the middle process emulating the two real hosts. Because they operate at the application layer, proxy servers are also referred to as application layer firewalls.

Stateful multi-layer inspection (smli)

@The Stateful multi-layer inspection (SMLI) firewall is similar to application level gateways in the sense that all levels of the OSI model are inspected carefully right from the network wire to the IP application layer. @The SMLI firewalls are different from the conventional “stand in” proxies in a way that the stand-in proxies are used for the applications when communicating to the outside world, thus putting a heavy processing load on the processors. In contrast, the SMLI firewall just examines each packet and compares them against the known states (i.e. bit patterns) to know about the behaviour pattern of the acceptable packets.@The term stateful implies that the firewall is wakeful and is capable of remembering the state of each session of packet exchange across it, allowing it to monitor all the packets for unauthorised access while maintaining high level of security, even with connectionless service protocols such as UDP, SMTP, etc.

Communication cables

Coaxial cable@Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield @ The metal shield helps to block any outside interference from Although coaxial cabling is difficult to install, it is highly resistant to signal interference. In addition, it can support greater cable lengths between network devices than twisted pair cable.@ The two types of coaxial Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate maximum segment length being 200 meters. In actual fact the maximum segment length is 185 meters. Thin coaxial cable has been popular in Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters

Fiber optic cabling@Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials (See fig. 5). It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between @Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services.Socks@ SOCKS combine powerful features of circuit-level proxies without the programming overhead of traditional application-level firewalls. A number of companies, including IBM, DEC, Cyber guard, etc. have commercial firewall products deploying the SOCKS protocol@SOCKS are an open, industry-standard protocol advanced by the Authenticated Firewall Traversal working group of the IETF (Internet Engineering Task Force).@SOCKS are a networking middleware: a circuit-level gateway, acting as a proxy and is placed at the session layer to mediate client/server connections.@There are a number of products based on SOCKS specifications such as Auto SOCKS available in the market. The latest version is SOCKS 5, which is backward compatible with previous versions as well as supporting key features such as authentication, encryption, the UDP protocol, DNS and IP addressing

Encryption/Decryption methods@Public Key Infrastructure (PKI) A PKI (public key infrastructure) enables users of a basically unsecure public network such as the Internet to securely and privately exchange data and money through the use of a public and a private cryptographic key pair that is obtained and shared through a trusted authority. The public key infrastructure provides for a digital certificate that can identify an individual or an organization and directory services that can store and, when necessary, revoke the certificates.@The public key infrastructure assumes the use of public key cryptography, which is the most common method on the Internet for authenticating a message sender or encrypting a message. @Traditional cryptography has usually involved the creation and sharing of a secret key for the encryption and decryption of messages. This secret or private key system has the significant flaw that if the key is discovered or intercepted by someone else, messages can easily be decryptedA public key infrastructure consists of:@A certificate authority (CA) that issues and verifies digital certificate. A certificate includes the public key or information about the public key@A registration authority (RA) that acts as the verifier for the certificate@authority before a digital certificate is issued to a requestor@One or more directories where the certificates (with their public keys) are held@A certificate management system

@Web server security

through SSL (Secure

Socket Layer) @Secure Sockets Layer, a protocol developed by Netscape for transmitting private documents via the Internet. SSL uses a cryptographic system that uses two keys to encrypt data − a public key known to everyone and a private or secret key known only to the recipient of the message. Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to obtain confidential user information, such as credit card numbers.

By convention, URLs that require an SSL connection start with https: instead of http

@Another protocol for transmitting data securely over the World Wide

Web is Secure HTTP (S-HTTP). Whereas SSL creates a secure

connection between a client and a server, over which any amount of data can be sent securely, S-HTTP

Security Policy@The scope of security policy depends on aspects such as the size of the Intranet site, type of information hosted on it, and the number of users accessing the site.@ Each policy is based on a number of parameters like the companies’ business rules, objectives, Intranet type, content, and existing security infrastructure.@ It should be noted that a security policy made for some other Intranet cannot be used for a different intranet by merely changing the name. @Although, an Intranet security policy is a very broad topic and it cannot be covered easily in few pages since it differs from situation to situation, there are some general principles that can be found similar in almost all policies. Some of them are as follows:

@Identification of • The content, and needs to be secured • User groups or categories

@ Procedures • Access authorization

procedure • Backup procedures • Disaster recovery procedures

@Action against misuse • Course of action in the event of misuse or

attacks • Ensuring employees

exercise proper etiquette so that they do not misrepresent the company

• Handling sensitive or secured documents stored on the intranet site

• Copyright policies for intellectual properties developed by the company. Network Service Access Policy: A high-level, issue-specific policy which defines those services that are allowed or denied from the restricted network. It also contains clear guidelines giving instructions detailing the way in which these services will be used, and the conditions for exceptions to this policy, if any. Firewall Design Policy: A lower-level policy that describes how the firewall will handle prevention of access and filtering of services as defined in the above network service access policy

What is Telnet?Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. Through Telnet, an administrator or another user can access someone else's computer remotely. On the Web, HTTP and FTP protocols allow you to request specific files from remote computers, but not to actually be logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer.A Telnet command request looks like this (the computer name is made-up):telnet the.libraryat.whatis.edu

SQL/API@The Structured Query

Open Database Connectivity (ODBC)@Open Database Connectivity (ODBC) is a specification for an application programming interface (API) that enables applications to access multiple database management systems using Structured Query Language (SQL). @Using the ODBC interface in your COBOL applications, you can dynamically access databases and file systems that support the ODBC interface. @ ODBC permits maximum interoperability: a single application can access many different database management systems.@ This interoperability enables you to develop, compile, and ship an application without

targeting a specific type of data source.@ When you use the ODBC interface, your application makes calls through a driver manager. The driver manager dynamically loads the necessary driver for the database server to which the application connects.

(ODBC)

Disk quotas@ Disk quotas are used to track the use of disk space for each user. They are normally disabled and are only supported on NTFS file systems. Quotas are tracked per partition and per user using ownership information to account for resource use. Compressed file sizes are measured according to the uncompressed file size. @Disk quotas may be viewed and administered by using the “Disk Management” tool to select the properties dialog box of the disk or volume. The “Quota” tab contains quota information and management functions. Quota management must be enabled. @Warning levels may be set and hard limits may also be set. Disk space may be denied to users who exceed their quota limit. The events may be logged when the user exceeds their warning and/or quota limit. @Windows Explorer can be used to set up and monitor disk quotas. The following options are available in Windows Explorer under local disk properties@General @Tools @Hardware @Sharing @Security @Web Sharing

Java Database Connectivity (JDBC)

(JDBC)

@JDBC is an application programmer's interface for accessing relational databases from Java programs. @Oracle Late supplies a native JDBC driver that allows Java applications to communicate directly with Oracle Lite's object-relational database engine. Oracle Lite's implementation of JDBC complies with JDBC 1.22. In addition, Oracle Lite provides certain extensions specified by JDBC 2.0. Oracle Lite's extensions are compatible with the Oracle8i JDBC implementation.@ For a complete JDBC reference, see the Sun Microsystems Web site.

Post Office Protocol (POP)

Post Office Protocol is an Internet Protocol standard that was developed so that individual users can connect to the Mail Exchanger (the mail server) and download their mail. A local client running on your machine with POP3 capability will connect to a Mail Exchanger using TCP on port 110 (or 109 if it uses POP2), download their mail messages, and log out of the server. This allows machines that are not connected to the Internet to still be able to send and receive e-mail.This is the protocol your Microsoft Outlook or Netscape Messenger uses to pull mail from your Internet Service Provider's mail server.

is designed to transmit individual messages securely.

Web authoring tools @CGI was considered excellent in the beginning since it was also open standard. The only drawback it suffered was that it was slow. Major software developers virtually ignored the CGI and consequently CGI could not survive the competition. @The need arose for addressing various issues related to Web programming. Software were required for establishing connection to ensure security, connectivity to databases, conversion of the results to Web format, and a lot more. @In response to the rising needs, numerous vendors have come up with numerous products. Some of them are listed below. @ IntraLaunch @ CodeCharge @Benefit Profiles Portal Suite @ Servicespace Suite consisting of Enterprise, Customer Portal, Partner Portal @LiveHelp @HTML/OS @WebSiteManager.

@This aspect of Web authoring and management tools is not being discussed here in detail since it has been covered in Unit 5 under the heading Web authoring and management tools.

Web browsersWeb browsers support two graphic formats: GIF and JPEG. Both formats use internal compression routines that make the graphics smaller, thus decreasing download times. When it is decided to put a graphic on the Web, it is important to decide whether to use GIF or JPEG.The JPEG FormatThe JPEG format, with its support for 16.7 million colors, is primarily intended for photographic images. The internal compression algorithm of the JPEG format, unlike the GIF format, actually throws out information. Depending on what settings you use, the thrown out data may or may not be visible to the eye. Once you lower the quality of an image, and save it, the extra data cannot be regained so be sure to save the original.

The GIF FormatThe GIF format is one of the most popular formats on the Internet. Not only is the format excellent at compressing areas of images with large areas of the same color, but it is also the only option for putting animation online (unless you want to use Flash or other vector-based animation formats, which typically cost more). The GIF89a format also supports transparency, and interlacing.GIF files support a maximum of 256 colors, which makes them practical for almost all graphics except photographs. The most common method of reducing the size of GIF files is to reduce the number of colors on the palette. It is important to note that GIF already uses the LZW compression scheme internally to make images as small

as possible without losing any data

Language/Application Programming Interface (SQL/API) is a function library designed for use with the C programming language, and development environments that support C-style external function calling conventions. SQL/API is a Call Level Interface (CLI) analogous to SQL*Net in Oracle environments and CT-LIB in Sybase environments. @One can make calls to SQL/API functions throughout the application to interact with SQL Base. @Typical function calls include connecting and disconnecting to a database, passing SQL statements to the server for compilation and execution, providing bind variable data, and retrieving result sets. Additionally, the SQL/API provides functions to perform administrative tasks such as performing database backups and restorations

Service Protocols

Many Internet users are familiar with the protocols such as TCP/IP to connect to the Internet. These include those protocols that permit the users to logon to remote computers, such as the following: • World Wide Web’s Hypertext

Transfer Protocol (HTTP) • File Transfer Protocol (FTP) • Telnet (Telnet) • User Datagram Protocol (UDP) • Simple Mail Transfer Protocol

(SMTP).

These and other protocols are often packaged together with TCP/IP as a “suite.” Protocols related to TCP/IP include the User Datagram Protocol (UDP), which is used instead of TCP for special purposes. In combination with the IP, it is known as the UDP/IP suite. Though not very well known otherwise, other protocols are used by network host computers for exchanging router information such as: • Internet Control Message

Protocol (ICMP) • Interior Gateway Protocol

(IGP) • Exterior Gateway Protocol

(EGP) • Border Gateway Protocol

(BGP).

Personal computer users connect to the Internet through the Serial Line Internet Protocol (SLIP) or the Point-to-Point Protocol (PPP).

Groupware@Groupware are a collection of software tools that encompass a broad range of applications. Even though groupware broadly consists of applications like calendars, project planning, sharing documents, emails, etc

@the use of groupware, users can easily do most of the office related management work, which otherwise would be extremely difficult. For instance, it would be possible to edit, analyse, share, store and retrieve document.

@The downside of groupware is that they are very costly and with the increase in complexity or additional features, the cost increases proportionately.

@However, since Intranets work purely on inexpensive browsers as front-ends and actual applications on the Web server as back-end, many a time the groupware proves to be cheaper, but such implementations are rare. @As long as the same operating system and hardware were used, there were no problems, but maintenance and technical support cost was extremely high.

Electronic commerce@Electronic commerce is one of the foremost fields that would straightaway be redefined to suit the needs of the world. This field is relatively very new and a good amount of development has already taken place with the deployment of certain e-commerce based protocols such as Agora, Millicent, etc.Agora Agora is a simple and inexpensive Web protocol for electronic commerce. The feature that makes the protocol most attractive is that it supports a high volume of transactions with low incurred cost. It has the following properties:

• Minimal: The incurred cost of Agora transactions is close to free Web browsing, where cost is determined by the number of messages.

• Distributed: Since Agora is fully distributed, traders and merchants can permit customers without access to a central authority. It becomes possible for the customers to purchase from any merchant provided that they have valid accounts.

• On-line arbitration: It is obvious that a number of disputes may arise in trade and commerce. With this property, an on-line arbitrator can settle certain customer/merchant disputes

Hardware and software requirementHardware

SMTPsimple Mail Transfer Protocol, a protocol for sending e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you need to specify both the POP or IMAP server and the SMTP server when you configure your e-mail application.

Internet Message Access Protocol( IMAP)

@IMAP (Internet Message Access Protocol) is a standard protocol for accessing e-mail from your local server.@ IMAP (the latest version is IMAP Version 4) is a client/server protocol in which e-mail is received and held for you by your Internet server. @You (or your e-mail client) can view just the heading and the sender of the letter and then decide whether to download the mail. @You can also create and manipulate multiple folders or mailboxes on the server, delete messages, or search for certain parts or an entire note.@ IMAP requires continual access to the server during the time that you are working with your mail.@ IMAP can be thought of as a remote file server. POP3 can be thought of as a "store-and-forward" service.

File Transfer Protocol (FTP)

File Transfer Protocol (FTP) is a standard Internet protocol for transmitting files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It's also commonly used to download programs and other files to your computer from other servers. As a user, you can use FTP with a simple command line interface (for example, from the Windows MS-DOS Prompt window) or with a commercial program that offers a graphical user interface. Your Web browser can also make FTP requests to download programs you select from a Web page. Using FTP, you can also update (delete, rename, move, and copy) files at a server. You need to logon to an FTP server. However, publicly available files are easily accessed using anonymous FTP.

Internet Protocol.the Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet. Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet. When you send or receive data (for example, an e-mail note or a Web page), the message gets divided into little chunks called packets. Each of these packets contains both the sender's Internet address and the receiver's address. Any packet is sent first to a gatewaycomputer that understands a small part of the Internet. The gateway computer reads the destination address and forwards the packet to an adjacent gateway that in turn reads the destination address and so forth across the Internet until one gateway recognizes the packet as belonging to a computer within its immediate neighborhood or domain. That gateway then forwards the packet directly to the computer whose address is specified.HTTP (Hypertext Transfer Protocol)

HTTP (Hypertext Transfer Protocol) is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. As soon as a Web user opens their Web browser, the user is indirectly making use of HTTP. HTTP is an application protocol that runs on top of the TCP/IP suite of protocols (the foundation protocols for the Internet). HTTP concepts include (as the Hypertext part of the name implies) the idea that files can contain references to other files whose selection will elicit additional transfer requests. Any Web server machine contains, in addition to the Web page files it can serve, an HTTP daemon, a program that is designed to wait for HTTP requests and handle them when they arrive. Your Web browser is an HTTP client, sending requests to server machines. When the browser user enters file requests by either "opening" a Web file (typing in a Uniform Resource Locator or URL) or clicking on a hypertext link, the browser builds an HTTP request and sends it to the Internet Protocol address (IP address) indicated by the URL.

Multiple Layers of Intranet SecurityAddress Resolution Protocol @(ARP) Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP address) to a physical machine address that is recognized in the local network. @For example, in IP Version 4, the most common level of IP in use today, an address is 32 bits long. @In an Ethernet local area network, however, addresses for attached devices are 48 bits long. (The physical machine address is also known as a Media Access Control or MAC address.) @A table, usually called the ARP cache, is used to maintain a correlation between each MAC address and its corresponding IP address. @ARP provides the protocol rules for making this correlation and providing address conversion in both directions.

How ARP WorksWhen an incoming packet destined for a host machine on a particular local area network arrives at a gateway, the gateway asks the ARP program to find a physical host or MAC address that matches the IP address. The ARP program looks in the ARP cache and, if it finds the address, provides it so that the packet can be converted to the right packet length and format and sent to the machine. If no entry is found for the IP address, ARP broadcasts a request packet in a special format to all the machines on the LAN to see if one machine knows that it has that IP address associated with it. A machine that recognizes the IP address as its own returns a reply so indicating. ARP updates the ARP cache for future reference and then sends the packet to the MAC address that replied.Address TranslationWhen a Web site address or URL is typed in the Web browser, as www.startv.com and not as a series of numbers, it is essential for the server to know where exactly the data has to be sent to or received from. This address is mapped on to (or translated into) a series of numbers. The translation is called “domain name resolving”, “host name resolving” or “name server lookup”. For instance, the VSNL site address www.vsnl.net.in would translate to a group of four octets like 202.30.15.30. The translation is done on the whole name and not on each byte between the periods.

The task of number translation is done solely by a domain name server (DNS) on the Intranet server. Like all devices, it has its own IP address (e.g., 194.62.15.20

SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it is limited in its ability to queue messages at the receiving end, it is usually used with one of two other protocols, POP3 or IMAP that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving e-mail. On Unix-based systems, sendmail is the most widely-used SMTP server for e-mail. A commercial package, Sendmail, includes a POP3 server. Microsoft Exchange includes an SMTP server and can also be set up to include POP3 support.SMTP usually is implemented to operate over Internet port 25. An alternative to SMTP that is widely used in Europe is X.400. Many mail servers now support Extended Simple Mail Transfer Protocol (ESMTP), which allows multimedia files to be delivered as e-mail.

Secure Electronic Transactions (SET) protocolSecure Electronic Transactions (SET) relies on the science of cryptography – theencoding and decoding messages. There are two primary encryption methods inuse today: secret-key cryptography and public-key cryptography. Secret-keycryptography is impractical for exchanging messages with a large group ofpreviously unknown correspondents

TCP (Transmission Control Protocol)TCP (Transmission Control Protocol) is a set of rules (protocol) used along with the Internet Protocol (IP) to send data in the form of message units between computers over the Internet. While IP takes care of handling the actual delivery of the data, TCP takes care of keeping track of the individual units of data (called packets) that a message is divided into for efficient routing through the Internet.For example, when an HTML file is sent to you from a Web server, the Transmission Control Protocol (TCP) program layer in that server divides the file into one or more packets, numbers the packets, and then forwards them individually to the IP program layer. Although each packet has the same destination IP address, it may get routed differently through the network. At the other end (the client program in your computer), TCP reassembles the individual packets and waits until they have arrived to forward them to you as a single file.

The MilliCent Protocol

@Communication costs are greatly reduced by verifying the scrip locally at the vendors site since there are almost no MilliCent-specific communication costs for a normal transaction. Moreover, no centralised server for account management or authentication is required. @ Brokers handling all accounts and billing related activities further reduce the accounting costs. After the customer opens an account with a specific broker; it becomes the responsibility of the broker to maintain and manage the accounts @In normal practice, especially in account-based schemes, the vendor maintains the account whereas in MilliCent, the customer himself maintains the account

GPRS@GPRS stands for General Packet Radio Service and is a second generation (2G) and third generation (3G)--or sometimes referred to as in-between both generations, 2.5G--wireless data service that extends GSM data capabilities for Internet access, multimedia messaging services, and early mobile Internet applications via the wireless application protocol (WAP), as well as other wireless data services.Features of GPRS@2G (second generation) GPRS service had data rates of 56-114 kit/second--akin to dial-up modem speeds.@GPRS wireless networks were later enhancing faster 3G (third generation) throughput speeds. T-Mobile's EDGE (enhanced Data Rates for Global Evolution), for

Applications of WAP Corporate applications that are being enhanced and enabled with a WAP interface include: • Remote Point of Sale • Customer Service • Remote Monitoring such as

Meter Reading • Vehicle Positioning • Corporate Email • Remote LAN Access • File Transfer • Web Browsing • Document Sharing/

Collaborative Working • Audio • Still Images • Moving Images • Home Automation

Consumer Applications that are being enhanced and enabled with a WAP interface include: • Simple Person to Person

Messaging • Voice and Fax Mail

Notifications • Unified Messaging • Internet Email • Prepayment • Ringtones • Mobile Commerce • Mobile Banking • Chat • Information Services.

Days are not far when WAP would be used to control airconditioners and refrigerators installed at home directly from anywhere in the world. Users would be able to switch on and regulate airconditioners much before coming back home. Similarly, it would be possible to program washing machines remotely.NSAPI (Netscape Server Application Programming Interface) is an (application program interface) that is provided with Netscape Web server to help developers build faster and more complex Web-based applications by extending the server capabilities. NSAPI, the Common Gateway Interface (CGI), and the Java and JavaScript-based server API are the three components of Netscape's Internet Application Framework. NSAPI was created as a more efficient and robust replacement for the Common Gateway Interface alone. It is often used to develop applications that involve custom authorization or logging, or to change aspects of server operation. NSAPI is usedo handle Hypertext Transfer Protocol transactions in the Netscape Enterprise Server's request-response process through its built-in Server Application Functions (SAF). Netscape Server's SAFs are written with the NSAPI and are functions called by the server to deal with requests received from a client. At start up, after initialization, the server waits for an HTTP request from the client for a resource such as an HTML file, a CGI program, or an image file, for example. The request consists of a Universal Resource Identifier (URI), an HTTP method, and,

Wireless Application Protocol (WAP)Intranet Protocols

Wireless Application Protocol

Wireless Application Protocol (WAP) is a suite of communication protocols for the wireless and mobile devices designed to access the internet independent of manufacturer, vendor, and technology. @The WAP was developed by the WAP Forum, a consortium of device manufacturers, service providers, content providers, and application developers. @WAP bridges the gap between the mobile world and the Internet as well as corporate intranets and offers the ability to deliver an unlimited range of mobile value-added services to subscribers—independent of their network, bearer, and terminal. @Mobile subscribers can access the same wealth of information from a pocket-sized device as they can from the desktop. WAP is a global standard and is not controlled by any single company.Common Gateway Interface (CGI)@An HTTP server is often used as a gateway to a legacy information system; for example, an existing body of documents or an existing database application. The Common Gateway Interface is an agreement between HTTP server implementers about how to integrate such gateway scripts and programs.@It is typically used in conjunction with HTML forms to build database applications

Common Gateway Interface1. That each time the application is executed, it runs as a separate process with its own address space resulting in execution of unnecessary extra instructions. @This could be troublesome especially when many instances of the same application are running. 2. That the execution speed is extremely slow. @It could be due to the references made by the applications, communication speed; the extremely slow compile/execute time and other factors.

Comman Gateway

over a public network. For a merchant toconduct transactions securely with millions of subscribers, each consumer wouldneed a distinct key assigned by that merchant and transmitted over a separatesecure channel. However, by using public-key cryptography, that same merchantcould create a public/private key pair and publish the public key, allowing any5consumer to send a secure message to that merchant. This is why SET usesboth methods in its encryption process. The secret-key cryptography used inSET is the well-known Data Encryption Standard (DES), which is used byfinancial institutions to encrypt PINs (personal identification numbers). And thepublic-key cryptography used in SET is RSA. In the following section, the usageof symmetric (secret-key) and asymmetric (public-key) key encryption in SET willbe discussed.

WAP Technology@The basic philosophy behind the WAP approach is to utilise fewest resources possible on the handheld terminals and to utilise all the functionality of the network.@ Micro browser-based services and applications reside temporarily on servers as well as on phones. In the design of the WAP the standard, application part has been kept separate from the bearer being used. This separation helps greatly in the switching over from ordinary applications like SMS or CSD to GPRS. In addition, the most important features of WAP are given below: @Compatibility with any mobile network standard such as Code Division Multiple Access (CDMA), Global System for Mobiles (GSM), or Universal Mobile Telephone System (3GSM). WAP has been designed to work with all cellular standards and is supported by almost all major wireless leaders such as Siemens, AT&T and NTT DoCoMo.

.

example, delivers up to 4 times the GPRS rate.@Both GPRS and Edge, however, are quickly being surpassed by even faster 4G (fourth generation) mobile data networks

Code division multiple access (CDMA) @Code-Division Multiple Access, a digital cellular technology that uses spread-spectrum techniques. @Unlike competing systems, such as GSM, that use TDMA, CDMA does not assign a specific frequency to each user. Instead, every channel uses the full available spectrum.@ Individual conversations are encoded with a pseudo-random digital sequence.@ CDMA consistently provides better capacity for voice and data communications than other commercial mobile technologies, allowing more subscribers to connect at any given time, and it is the common platform on which 3G technologies are built.

The benefits of CDMA: @ Increased connectivity time for portables @Bandwidth available on demand. @Near-universal geographical coverage. @Low equipment cost, both subscriber stations and fixed plant. @ Reduced installation time, error rates, inventory of components, maintenance, and many other related benefits. @ Enhanced privacy. @Improved coverage characteristics, allowing for possibility of fewer cell sites or minimum number of fixed radio sites.

Distributed mail system protocol (DMSP) Distributed Mail System Protocol (DMSP) is a lesser known message delivery protocol of the Intranet. The most interesting feature behind its philosophy is that it does not assume that all email messages are placed only on one mail server, as is the case with POP3 and IMAP.

It also offers the facility of multi-session connection for message delivery. In the first instance, it permits the users to download all the email messages from the server to a workstation, computer, or laptop and then disconnect. Now, the user is free to read and answer the email while the session remains disconnected. Whenever the user wishes, the session is established, emails are transferred and the system is automatically resynchronised.

sometimes, information about the client or the request.

Configuring web server@One of the popular Web servers is Apache. The current version of Apache Web server is 1.3.3-x. It is available free with Red Hat Linux 5.2, and can also be downloaded from http://www.apache.org.@ It sets up and gets ready to run automatically at boot as soon as the Linux installation is completed.@ The Apache Web server is extremely powerful, and can be configured to handle any kind of environment from a lightly loaded Intranet to a commercial heavily loaded Internet Web server taking more than 100,000 hits a day. @It is very simple to test the working of the Apache Web server. Simply point the browser to the URL http://localhost. The Apache’s default “It Worked” page starts up. The index.html file in the /home/httpd/html directory can be changed to start publishing pages on the Intranet. @The default configuration file /etc/httpd/conf/httpd.conf is suitable for simple configurations, though one might want to edit it if there is an unusually heavy load, or wish to configure a different machine name, port, or address to send error messages.Gateway@A node on a network that serves as an entrance to another network.@ In enterprises, the gateway is the computer that routes the traffic from a workstation to the outside network that is serving the Web pages.@ In homes, the gateway is the ISP that connects the user to the internet. @In enterprises, the gateway node often acts as a proxy server and a firewall. @The gateway is also associated with both a router, which use headers and forwarding tables to determine where packets are sent, and a switch, which provides the actual path for the packet in and out of the gateway. @A computer system located on earth that

Interface (CGI)The common gateway interface (CGI) is a standard way for a Web server to pass a Web user's request to an application program and to receive data back to forward to the user. When the user requests a Web page (for example, by clicking on a highlighted word or entering a Web site address), the server sends back the requested page. However, when a user fills out a form on a Web page and sends it in, it usually needs to be processed by an application program. The Web server typically passes the form information to a small application program that processes the data and may send back a confirmation message. This method or convention for passing data back and forth between the server and the application is called the common gateway interface (CGI). It is part of the Web's Hypertext Transfer Protocol (HTTP). f you are creating a Web site and want a CGI application to get control, you specify the name of the application in the uniform resource locator (URL) that you code in an HTML file. This URL can be specified as part of the FORMS tags if you are creating a form. For example, you might code:<FORM METHOD=POST ACTION=http://www.mybiz.com/cgi-bin/formprog.pl>

and the server at "mybiz.com" would pass control to the CGI application called "formprog.pl" to record the entered data and return a confirmation message. (The ".pl" indicates a program written in PERL but other languages could have been used.)UDP user datagram protocol@The User Datagram Protocol offers only a minimal transport service -- non-guaranteed datagram delivery -- and gives applications direct access to the datagram service of the IP layer. @UDP is used by applications that do not require the level of service of TCP or that wish to use communications services (e.g., multicast or broadcast delivery) not available from TCP.@UDP is almost a null protocol; the only services it provides over IP are checksumming of data and multiplexing by port number. Therefore, an application program running over UDP must deal directly with end-to-end communication problems that a connection-oriented protocol would have handled -- e.g., retransmission for reliable delivery, packetization and reassembly, flow control, congestion avoidance, etc., when these are required. The fairly complex coupling between IP and TCP will be mirrored in the coupling between UDP and many applications using UDP.UDP header:

Source Port. 16 bits.The port number of the sender. Cleared to zero if not used.Destination Port. 16 bits.The port this packet is addressed to.Length. 16 bits.The length in bytes of the UDP header and the encapsulated data. The minimum value for this field is 8.Checksum. 16 bits.Computed as the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded as needed with zero bytes at the end to make a multiple of two bytesData. Variable length.

Encryption/decryption

Wireless Application Environment (WAE): The WAE defines the user interface on the phone through the use of the Wireless Markup Language (WML), WMLScript is a scripting language similar to JavaScript and the Wireless Telephony Application (WTA). Wireless Session Protocol (WSP): A layer that links the WAE and the Wireless Transaction Protocol. Wireless Transaction Protocol (WTP): Responsible for ensuring proper wireless enabled transaction using protocols such as Wireless Datagram Protocol or standard suite of TCP/IP protocols. WTP offers three types of services: unreliable one way request, reliable one way request and reliable two way request respond. Wireless Transport Layer Security (WTLS): Just like the transport layer of the OSI model, the WTLS also provides security features that are based upon the established Transport Layer Security (TLS) protocol standard. It also extends services such as data integrity checks, privacy on the WAP Gateway to client, and authentication.

Wireless Datagram Protocol (WDP): This is a protocol very much similar to the UDP except that the WDP uses wireless communication techniques. @The SMS, CSD and the USSD are the three most important of the WAP’s underlying bearers: Short Message Service: Supports a maximum length of 160 characters per short message. @ Circuit Switched Data: Since CSD has very few users as of today, the WAP could not have a good start with the CSD as well.

What is an IP address?

@Computers communicate over the Internet using the IP protocol (Internet Protocol), which uses numerical addresses, called IP addresses, made up of four whole numbers (4 bytes) between 0 and 255 and written in the format xxx.xxx.xxx.xxx. For example, 194.153.205.26 is an IP address given in technical format. @These addresses are used by networked computers to communicate, so each computer on a network has a unique IP address on that networkExplain various classes of IP addresses?

IP addresses are divided into five IP classes: IP address class AIP address class BIP address class CIP address class DIP address class E

ISAPI (internet server application program interface)ISAPI (Internet Server Application Program Interface) is a set of Windows program calls that let you write a Web server application that will run faster than a common gateway interface (CGI) application. A disadvantage of a CGI application (or "executable file," as it is sometimes called) is that each time it is run, it runs as a separate process with its own address space, resulting in extra instructions that have to be performed, especially if many instances of it are running on behalf of users. Using ISAPI, you create a dynamic link library (DLL) application file that can run as part of the Hypertext Transport Protocol (HTTP) application's process and address space. The DLL files are loaded into the computer when HTTP is started and remain there as long as they are needed; they don't have to be located and read into storage as frequently as a CGI application. Existing CGI applications can be converted into ISAPI application DLLs without having to rewrite their logic. However, they do need to be written to be thread-safe so that a single instance of the DLL can serve multiple users.A special kind of ISAPI DLL is called an ISAPI filter, which can be designated to receive control for every HTTP request. You can create an ISAPI filter for encryption or decryption, for logging, for request screening, or for other purposes

A LAN (local area network) is a group of computers and network devices connected together, usually within the same building. By definition, the connections must be high speed and relatively inexpensive (e.g., token ring or Ethernet). Most Indiana University Bloomington departments are on LANs. For more, see What is a LAN (local area network)? A LAN connection is a high-speed connection to a LAN. On the IUB campus, most connections are either Ethernet (10Mbps) or Fast Ethernet (100Mbps), and a few locations have Gigabit Ethernet (1000Mbps) connections.A MAN (metropolitan area network) is a larger network that usually spans several buildings in the same city or town. The IUB network is an example of a MAN. A WAN (wide area network), in comparison to a MAN, is not restricted to a geographical location, although it might be confined within the bounds of a state or country. A WAN connects several LANs, and may be limited to an enterprise (a corporation or an organization) or accessible to

switches data signals and voice signals between satellites and terrestrial networks. @An earlier term for router, though now obsolete in this sense as router is commonly used.

GSMGlobal System for MobileGSM stands for Global System for Mobile Communications. Just like computers, mobile phones have evolved over time. @There were first generation mobile phones in the 70's, there are 2nd generation mobile phones in the 80's and 90's, and now there are 3rd gen phones which are about to enter the Indian market@. GSM is called a 2nd generation, or 2G communications technology.@Now, GSM makes use of two principles. The first called Time division Multiplexing is very simple. Let's say that one of your friends possesses the new and sleek Apple's IPhone.@ On the same lines, in GSM, the radio frequency say 890 Mhz is shared by different users in timeNow, GSM uses a combination of TDMA and FDMA. @This means that users A and B are not only sharing the channel in time but also frequency. @This means that user A is on the channel 890Mhz for 2 seconds, then jumps to 900Mhz channel for the next to seconds, then jumps to 910Mhz for the next 2 seconds and so on... Thus, each user is uses a different frequency at different time slots.@ This is called Frequency HoppingWhat is a centralized database@Centralized Systems: A modern, general-purpose computer system consists of one to a few CPUs & a number of device controllers that are connected through a common bus that provides access to shared memory. @The CPUs have local cache memories that store local copies of parts of the memory, to speed up access to data. @Each device controller is in charge of a specific type of device (for example, a disk drive, an audio device, or a video display). The CPUs & the device controllers can execute concurrently, competing for memory access. @Cache memory reduces the contention for memory access, since it reduces the number of times that the CPU needs to access shared memory. @In a distributed database system, the database is stored on several computers. The computers in a distributed system communicate with one another through various communication media, such as high-speed networks or telephone lines. @They do not share main memory or disks.Centralized and distributed database systems@In a distributed database environment, mainframe computers may be needed at corporate or regional headquarters to maintain sensitive corporate data, while clients at remote sites use minicomputers and server-class workstations for local processing.Both centralized and distributed database systems must deal with the problems associated with remote access: @Network response slows when WAN traffic is heavy. For example, a mission-critical transaction-processing application may be adversely affected when a decision-support application requests a large number of rows.@A centralized data server can become a bottleneck as a large user community contends for data server access.@Data is unavailable when a failure occurs on the network.

using by SSL@Once a session is established, the SSL generates a session key using public-key encryption to exchange information between the client and server. @This key is used to encrypt the transaction for both request as well as the response. It would be extremely difficult for the attacker to get into the system since each transaction uses a different session key. @Hence, even if the attacker succeeds in cracking the code of a transaction, he cannot use the same key every time for cracking and will have to spend an enormous amount of time as he did for decrypting the first key.

@Most of the server and browser software developed by various vendors carry out encryption using either a 40-bit or a 128-bit secret key. It is felt that using a 40-bit key could be insecure since any possible combination of 2^40 can be computed easily using modern day computers.@ Compared to this, the use of a 128-bit key eliminates this problem as there would be 2^128 possible combinations instead of just 2^40. @Software are coming up in which the user can select the kind of security measure required to be taken for encryption. One such example is the Netscape, in which the user can select from available encryption methods and size of key.

Remote Login: telnet

In a similar manner to ftp allowing a user to transfer files across the Internet, telnet allows users to log onto and work on remote machines as if they were sitting at one of its terminals. How usable this remote login is depends on how well the machines are connected and how well your terminal is recognized by the foreign machine. As the distance between machines increases, and the number of networks that must be interconnected (the number of hops), the response time between a user entering a character and the remote machine responding to it increases. You can measure this round trip time with the ping command as discussed in Chapter 2. If the ping times are greater than 500 milliseconds, the remote machine will seem unresponsive and you will find it hard to be productive. Slow connections are common when using machines at far-removed different sites. If you are of the patient type, your telnet session will be usable but editing may be difficult.     Telnet has very few options and is simple to use. Like ftp you just give the name of the machine you want to connect to as an option:

% telnet itasca.thomas.hal.com Login to the machine

itasca. Connected to itasca.thomas.hal.com. Escape character is '^]'.

The escape character may be ^] or t. SunOS UNIX (itasca) login: Now we can login.

iServer iServer was developed by Servertec,

All IP addresses are placed in a particular class based on the decimal values of their first octets. In the first octet, an IP address can start with a decimal value between 1 and 255.

IP class A addresses have first octets with a decimal number from 1 to 127. Example:27.x.y.z102.x.y.z

IP class B addresses have first octets with a decimal number from 128 to 191.Example:128.x.y.z151.x.y.z

IP class C addresses have first octets with a decimal number from 192 to 223.Example:192.x.y.z223.x.y.z

IP class D addresses have decimal values from 224 to 239 in the first octet, and the 4 leftmost bits are 1110.Example:224.x.y.z239.x.y.z

The last IP address class of addresses is IP class E. IP class E addresses range from 240 to 255 in the first octet, and the 4 leftmost bits are 1111. Example:240.x.y.z255.x.y.z

Secure Sockets Layer(SSL)Secure Sockets Layer, a protocol developed by Netscape for transmitting private documents via the Internet. SSL uses a cryptographic system that uses two keys to encrypt data − a public key known to everyone and a private or secret key known only to the recipient of the message. Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to obtain confidential user information, such as credit card numbers. By convention, URLs that require an SSL connection start with https: instead of http Another protocol for transmitting data securely over the World Wide Web is Secure HTTP (S-HTTP). Whereas SSL creates a secure connection between a client and a server, over which any amount of data can be sent securely, S-HTTP is designed to transmit individual messages securely. SSL and S-HTTP, therefore, can be seen as complementary rather than competing technologies. Both protocols have been approved by the Internet Engineering Task Force (IETF) as a standard

What is a Protocol ? List any two protocolsThat are supported by IntranetThere are rules governing how data is transferred over networks, how they are compressed, how they are presented on the screen and so on.

the public. The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN.

What are distributed database?Advantages@A database that consists of two or more data files located at different sites on a computer network.@ Because the database is distributed, different users can access it without interfering with one another. However, the DBMS must periodically synchronize the scattered databases to make sure that they all have consistent data@Distributed database advantages @There are a number of advantages to using a distributed DBMS. These include the followingCapacity and growth An advantage of distributed databases is that as the organisation grows, new sites can be added with little or no upheaval to the DBMS. Compare this to the situation in a centralised system, where growth entails upgrading with changes in hardware and software that effect the entire database. Reliability and availability An advantage of distributed databases is that even when a portion of a system (i.e. A local site) is down, the overall system remains available. With replicated data, the failure of one site still allows access to the replicated copy of the data from another site. The remaining sites continue to function. The greater accessibility enhances the reliability of the system.Efficiency and flexibility An advantage of distributed databases is that data is physically stored close to the anticipated point of use. Hence if usage patterns change then data can be dynamically moved or replicated to where it is most needed.

WebmasterA Webmaster is a person who either:@Creates and manages the information content (words and pictures) and organization of a Web site@Manages the computer server and technical programming aspects of a Web site@Companies advertising for a Webmaster vary in their use of the term. In a smaller company, a Webmaster typically "does it all."@ In a larger company, a Webmaster tends to be someone with either a writing and/or graphics design background who has acquired Web site creation skills (mainly knowledge and experience with HTML ) or a more technical person with some programming skills. @The "technical" Webmaster runs the server (for example, by managing the creation and authorization associated with file systems) and writes programs or Practical Extraction and Reporting Language scripts required by the Web site

AOL serverAOLserver, America Online’s own Web server, is the backbone of one of the largest and busiest production environments in the world. AOLserver is a multithreaded, Tcl-enabled Web server used for large scale, dynamic Websites. AOLserver powers America Online properties such as AOL.COM, Digital City, AOLMail, AOL Hometown, Helping.org, AOL Search, and much, much more.WYSIWYG kind of output: The software tool should generate output exactly as designed and laid out by the developers. If the developer designs the page in a particular format, it is essential for the editor to provide coding in a manner to generate the same output.

written entirely in Java for any Java-enabled operating system. It has the dual purpose of serving both Web pages as well as Java servlets. In other words, this is a special kind of product that offers the functionality of both a Web server as well as an application server.Internet Information ServerBetter and clearly documented security policies • Support for the new WebDAV publishing standards • Faster restarts of both Web and FTP services. • Support of clustering, Microsoft has significantly improved the configuration and setup to enable multiple machines to share the load and deliver more reliable Web services. Transport Layer security using SSL 3.0. • Digest Authentication (a method of hashing authentication information introduced in IE 5.0).ActiveX Data Object Support: New properties and methods to provide a tighter integration with the editor tools should be provided. Popular Web authoring tools (e.g., Macromedia’s Dreamweaver UltraDev, Adobe GoLive!) give this support.Site map: A proper view or estimate of how the Web site is organised and how massive it is makes the Web site more attractive. Editors should provide a broad view of the Web in the form of an GIF or JPG image whereas some even provide this as a Web page.Clipart support: Most editors come with a huge gallery of clipart and some even provide a collection of sounds, music and multimedia clips. Though, this is optional, it is desirable to provide one such library to enable the developers to use ready available objects

These set of rules are called protocols. There are many protocols, each one governing the way a certain technology works. For example, the IP protocol defines a set of rules governing the way computers use IP packets to send data over the Internet or any other IP-based network. It also defines addressing in IPTCP: Transmission Control Protocol, used for the reliable transmission of data over a network. HTTP: Hypertext Transfer Protocol, used for transmitting and displaying information in the form of web pages on browsers. FTP: File Transfer Protocol, used for file transfer (uploading and downloading) over the Internet SMTP: Simple Mail Transfer Protocol, used for email Ethernet: Used for data transmission over a LAN. Wi-Fi: One of the wireless protocols. Telnet over TCP/IPOn the Internet, the ability to connect with another machine is made possible by the Transmission Control Protocol (TCP), which enables two machines to transmit data back and forth in a manner coherent to the operating systems of each device, and the Internet Protocol (IP), which provides a unique, 32-bit address for each machine connected to the network. The telecommunications application built over these capabilities provides the local terminal with the means to emulate a terminal compatible with the remote computer.Connection Establishment : The Telnet TCP connection is established between the user?s port U and the server?s port L. The server listens on it?s well-known port L for such connections. Since a TCP connection is full-duplex and indentified by the pair of ports, the server can engage in many simultaneous connections involving it?s port L and different user ports U. Port Assignment - When used for remote user access to service hosts, this protocol is assigned server port 23, that is L = 23.

WN Web Server WN is a free Web server that runs on a number of variants of UNIX platforms. It provides support for both the major standards, HTTP 1.1 and CGI 1.1. In the WN server, the method of operation is unique and easy. The server is not based on file extensions but a separate database, called “index” is maintained in which the filename, extension, type, security information, etc., are entered. All requests or references are checked with the entries in the index. A file is loaded only when there is a reference and permission for execution or service. The WN does not serve files unless specifically instructed by the index Obviously, the database called index makes the process of searching the Website very easy. This is in line with the basic objective of WN to create an easy-to-search Website. It becomes possible for the end users to search for desired data in many different ways and in different portions of the files.

GIF: Graphics Interchange Format: A type of graphics file found frequently on the net. A picture of a vice-president, for example, may appear on the Intranet as a GIF. JPEG: Stands for Joint Photographic

Samba Server Samba is an excellent Web server software and has taken a lead further by being functional, reliable, and free. Samba 5.0 is the latest version and provides the following features:It is functional, that means Samba not only works like the server but also works very well in a wide variety of applications. At any time, if it is found that the server does not work according to the desired pattern, the system administrator can program APIs using languages like C and C++. • A Web-based step-by-step guidelines are available for configuration of Samba. It Supports ASP Web pages via the Samba Server CScript language so that the system administrators can create dynamic and database-driven Web pages. • Samba uses the HTTPS protocol in both 40- and 128-bit versions. Also, the OpenSSL libraries are supported.*Samba can run as a Windows NT System Service by executing a file named ntserver.exe binary in the “bin” directory.Kerberos V5: An Internet standard authentication protocol which is the default protocol for Windows 2000 computers within a domain. • Windows NT LAN Manager (NTLM): Used to authenticate users from Windows 95, 98, and NT systems. Windows 2000 Active Directory must be operating in mixed mode to use this authentication method

Samba server

Experts Group. A standard format of storing digitized, colour, or black-and-white photographs. JPEG files are smaller than corresponding GIF filesISDN: Stands for Integrated Services Digital Network. It is a way to move more data over existing regular phone lines. ISDN is rapidly becoming available to almost every country, and every one who needs it, at desired data transfer rates. In most countries it is available at a price comparable to standard analog phone line connectivity. It can provide speeds of roughly 128 kilobits per second (kbps) over regular phone linesClipart support: Most editors come with a huge gallery of clipart and some even provide a collection of sounds, music and multimedia clips. Though, this is optional, it is desirable to provide one such library to enable the developers to use ready available objects.