Practical TCP/IP and Ethernet Networking- P47 ppsx

212 Practical TCP/IP and Ethernet Networking with whom they are working. It is possible to incorporate live action color video and voice with shared workspace on the PC screen over the Internet. VidCall uses anyone of over 25 inexpensive video capture boards (including digital plug and play cameras) to transmit still and motion video. Depending on the speed of the computer modem, VGA display and LAN/WAN, virtual motion of up to 10 frames per second is achievable. Multi-point video and document conferencing is available over LAN/WAN accommodating up to 10 participants who can be located across the globe. VidCall also supplies additional freeware for registered VidCall users on the Internet. WhoIsThere enables individuals to setup their own user groups and to be informed as soon as members of their group are logging in to the video conference. 13.10.2 Video networking Another company providing video networking and video conferencing software is BitField. BitField claims to be the first company to have provided a complete H320 compatible video codec on a single PC video adapter board. Their video communication products turn PCs into video communication workstations, transferring full motion video between standard PCs via ISDN, LANs, and other communication networks. Since the products utilize existing PC and networking technology, they can be applied in many areas where traditional video equipment is too expensive and flexible. 13.11 News 13.11.1 News push The original approach to news via the Internet has been to search the World Wide Web and ‘pull down’ relevant news items. This is not only time consuming but also costly for an individual who has to connect through an ISP. On the other hand, products such as PointCast aggregate news from more than 700 sources, process this in a central broadcast facility and then broadcast it world-wide via the Internet. Only the news categories selected by the user is PUSHED down for collection every morning. PointCast delivers national, international, business, industry and company news, stock quotes, sports scores, weather reports, entertainment news and more. Currently, it acquires information from sources such as CNN, CNNfn, NY Times, Wall Street Journal, Reuters, Business Wire, PR News Wire, Standard and Poor’s ComStock, Sports Ticker and AccuWeather. PointCast network will work with a dial-up connection, as long as the dial-up connection assigns a valid IP Address. The PointCast network offers support for viewers using CompuServe, Shiva, FTP and Windows 95 Internet dialers. As for the on-line services, it depends on how they implement the Internet access. Currently, PointCast will work with CompuServe, America On-line and MicroSoft Network. From an enterprise point of view, PointCast allows management to selectively broadcast news to all employees using the existing network infrastructure, keeping in mind that PointCast is completely free thanks to commercial advertisers. To help the system administrator customize the PointCast Network, PointCast offers a suite of free tools, the so-called Intranet Broadcast Solution which allows the following: • It ensures that important company news is widely seen and read by broadcasting it directly to employees desktops via a private Intranet channel on PointCast The Internet for communications 213 • It allows the management to effectively communicate time sensitive messages through special windows on employees’ desktops • It empowers ‘knowledge workers’ by supplying all the news they need to be competitive including news from customers, suppliers, competitors and industry 13.11.2 News pull Individual publications The conventional pull services are still widely available with many private newspapers maintaining their own webster. A particular case in point is the South African based East London Daily Dispatch, which is widely read by Australian-based South African expatriates living in Australia. Collated news IBM Internet Connection Services offers a news service to subscribers available in 10 different languages and utilizing a news search engine that pulls stories from over 250 news sources from over the globe. Topics include top stories in technology, politics, business, culture news, CAN world news, TechWeb and USA today. It is also possible to select world news on a regional basis. 13.11.3 News groups: USENET While web (www) sites have received most of the attention from software developers and the press, the Internet’s news and conferencing service, USENET, represents another major Internet resource. USENET is based on news groups, such as comp.client.server or misc.education.adult, that contain articles similar to e-mail messages. News groups exist for virtually every conceivable professional and personal interest. Some news groups serve as problem solving forums and as the ‘help desks’ of the Internet. Most news groups are public and can be viewed anywhere the Internet reaches. Anyone with a news client and an Internet connection can submit an article. Some news group’s subject articles to a screening prior to publication, others automatically distribute all submissions. World wide, over 300 000 articles are posted each day to over 50 000 news groups. Because of the massive storage requirements, articles begin to disappear within a few days of publication. Stand-alone news client software is available from several sources. News clients are also built into Netscape Navigator and Microsoft Internet Explorer. As users of these web browsers become more experienced, they are able to ‘graduate’ to the world of USENET news. There are several packages available for dealing with USENET and many of them are available as freeware. We will now deal with some of them: 13.11.4 Search agents The question may well be asked: Why on earth would a company care about USENET postings? Here are a few reasons: • Find out who is mentioning your products • Find out who is using or misusing your trademarks • Discover people and companies looking for solutions that your organization can provide 214 Practical TCP/IP and Ethernet Networking • Find out what people are saying about your competitors’ products and services • Detect imposters forging messages that appear to originate from your organization A good example of a USENET search agent is NewsMonger by TechSmith Corporation. NewsMonger constructs the search query for you, or allows you to create the query yourself. It searches public USENET groups for each of your active queries using Digital’s Alta Vista engine. It removes duplicate articles and identifies new submissions. It then notifies you via e-mail when articles matching your criteria are discovered. A similar product is OUI (off-line user interface), which has the ability to locate, retrieve, download and post information to and from news groups. Upload utilities AutoPost is a program, which is capable UUEncoding files, and automatically uploading them to a new server, i.e. it automates the process of posting large volumes of files to news services. Retrieval programs There are several downloading programs for USENET, available as either shareware or freeware. Programs worth noting are: • Agent • Free Agent • News XPress • Pluckit 3 • SBNews; NewsRobot Functions of these packages include on-line/off-line news reading, e-mail functionality, built-in viewers for graphics files, and the ability to launch URLs, firewall protection, spam elimination, and automatic encryption to protect sensitive images. The prospective user will have to peruse the specifications and make a decision as to the most suitable package for a particular application. 13.12 Additional information Additional details about products mentioned in this chapter can be obtained from the following web sites. 13.12.1 Internet telephony PGPfone (Pretty Good Privacy Phone): http://web.mit.edu Net2Phone: http://www.net2phone.com FreeTel: http://www.freetel.com Internet Phone Release 5: http://www.vocaltec.com Internet Phone Call Waiting: http://www.vocaltec.com Aplio (Voice over IP): http://www.voiceoverip.sitehosting.net NetPhone IPBX: http://www.netphone.com WebPhone: http://www.netspeak.com Net2Phonepro: http:/www.net2phonepro.com The Internet for communications 215 13.12.2 Video conferencing VidCall: http://www.powernethk.com PictureTel: http://picturetel.com BitField: http://www.bitfield.fi VidCall has a ‘continuously running’ demo system with IP Address 205.157.131.91. First download and register the demo program, then ping the demo system to make sure it is running, then follow the steps supplied on the screen. 13.12.3 Paging SMS (Small Message Services): http://www.mobiledata.co.za 13.12.4 Fax Net2Fax: http://www.net2phone.com VocalTec PASSaFAX: http://www.vocaltec.com 13.12.5 Voice communication via web page link Click2Talk: http://www.net2phone.com Click2CallMe: http://www.net2phone.com Mini WebPhone: http://www.netspeak.com 13.12.6 Voice mail Internet Voice Mail: http://www.vocaltec.com QualComm: http://eudora.qualcomm.com BitWare: http://www.cheyenne.com 13.12.7 News services NewsMonger: http://www.techsmith.com PointCast: http://www.pointcast.com Commercial News Services on the Internet (listing) : http://www.jou.ufl.edu WebGate: http://ngw.webgate.net CNN Interactive: http://www.ibm.net UseNet News Readers: http://tucows.netactive.co.za East London Daily Dispatch: http://www.dispatch.co.za 13.12.8 PPP servers Foray PPP Remote Access Server: http://www.techsmith.com 13.12.9 E-mail Hotmail: http://www.hotmail.com Eudora Webmail: http://www.eudoramail.com Eudora Lite: http://www.eudora.com Voice e-mail: http://eudora.qualcom.com 14 9KI[XOZ_IUTYOJKXGZOUTY  5HPKIZO\KY When you have completed study of this chapter you should be able to: • Explain the security problem • Define the ways of controlling access to a network  :NKYKI[XOZ_VXUHRKS Although people tend to refer to the ‘Internet’ as one global entity, there are in fact three clearly defined subsets of this global network. Four, in fact, if one wishes to include the so-called ‘community network’. It just depends on where the conceptual boundaries are drawn. • In the center is the in-house corporate ‘intranet’, primarily for the benefit of the people within the organization • The intranet is surrounded by the ‘extranet’, exterior to the organization yet restricted to access by business partners, customers and preferred suppliers • Third, and this is optional, there can be a ‘community’ layer around the extranet. This space is shared with a particular community of interest, e.g. industry associations • Finally, these three layers are surrounded by the global Internet as we know it, which is shared by prospective clients/customers and the rest of the world This expansion of the Internet into organizations, in fact right down to the factory floor, has opened the door to incredible opportunities. Unfortunately it has also opened the door to pirates and hackers. Therefore, as the use of the Internet, intranets, and extranets has grown, so has the need for security. The TCP/IP protocols and network technologies are inherently designed to be open in order to allow interoperability. Therefore, unless proper precautions are taken, data can readily be intercepted and altered – often without either the sending or the receiving party being aware of the security breach. Because dedicated . people and companies looking for solutions that your organization can provide 214 Practical TCP/IP and Ethernet Networking • Find out what people are saying about your competitors’ products and. 212 Practical TCP/IP and Ethernet Networking with whom they are working. It is possible to incorporate live action color video and voice with shared workspace on. opened the door to pirates and hackers. Therefore, as the use of the Internet, intranets, and extranets has grown, so has the need for security. The TCP/IP protocols and network technologies are