Internet Services:

The world of the Internet Service Provider is an interesting one because it includes both halves of the client-server pair. On the one hand, clients of an ISP might dial in to the ISP's machine and access Internet services from there. On the other hand, users from across the Internet might wish to view a World Wide Web page of a merchant that the ISP supports.

The various services an ISP might offer or exploit include (in no particular order):

• Electronic mail - communication with users throughout the world; many say that 30,000,000 people are connected to the Internet. E-mail can be served to users directly on a server or to their PC via the POP mail protocol and publically available (free) programs like Eudora.
• Graphical World Wide Web (WWW) Browsing - The WWW is the Internet's `killer application'. It's easy to use, full of places to `visit', and easy to hype. It includes graphics, text, the occasional sound bite (multimedia), and the rare quick-time movie.
• Text-based World Wide Web Browsing - For users without a graphic connection to their ISP, the lynx program offers WWW browsing without the pictures.
• File transfers (both in and out of the ISP's site) - The FTP protocol is one of the Internet's most widely used services. It moves files in or out of your site.
• IRC (the Internet Relay Chat program) - The IRC program includes hundreds of public and private `chat areas' with topics that span the entire gamut of human interests. Chat in English or a dozen different foreign languages in a real-time discussion forum with people across the globe.
• USENET newsgroups - Also known as Netnews , each these public discussion forums resembles a computer bulletin board (BBS). Newsgroups facilitate discussions with thousands of global users who post `articles' that can then be viewed at any time in the future by readers (who often reply). USENET newsgroups generate hundreds of thousands of pages of discussion every day.
• Dialin line IP connections via SLIP or PPP to ISP customers - The essence of full Internet connectivity is access via the TCP/IP protocol. Providing SLIP or PPP access to ISP customers enables them to enjoy all the services listed here from their site. This means that all graphical capabilities (like WWW) are available to the consumer of a PPP/SLIP line.
• Archie access - Archie is a program that keeps track of files on hundreds of Internet sites. Archie usually resides at other sites and is accessed over the net by users at your site.
• Veronica - Veronica (provided at other sites) searches WWW sites for various information. Like Archie, Veronica resides on other people's sites.
• Gopher - Gopher is a file retrieval program popular with the BBS community. Its functionality is now included in World Wide Web browsers. Gopher servers enable a simple access technique to transfer information at your site to others as they request it via gopher and WWW.
• WAIS - WAIS is a text searching service. If you wish to WAIS-ify documents that your site creates and makes available to the Internet, plan to spend some time performing local configuration. Visiting other WAIS sites via the net is easy, of course.

Communications Protocols

Just as humans use certain rules and schemes for communications, so do computers. Interestingly enough, the world of 1's and 0's includes many different ways to communicate information. Each of these ways is called a `Communications Protocol' or just `Protocol'. The Internet uses the TCP/IP protocol. Sometimes other protocols are `encapsulated' in the TCP/IP protocol to be moved from one point to another, but generally TCP/IP is the lingua franca of the Internet.

When using TCP/IP on telephone lines, one of two schemes is used: SLIP or PPP. These protocols frame the TCP/IP packets correctly onto the phone line and deliver them to the other end. PPP can also transport other protocols, but that won't be discussed here.