· E-mail E-mail permeates most organizations. TCP/IP suite options for e-mail include proprietary messaging systems, as well as messaging systems that follow standards, such as Simple Mail Transfer Protocol (SMTP), Post Office Protocol version 3 (POP3) and Internet Mail Access Protocol version 4 (IMAP4). Most TCP/IP-applications suites include a POP3 e-mail client. When choosing your TCP/IP applications suite, make sure the inclu ded e-mail client is closely tied to your messaging strategy and the type of mail server implemented.

· X Windows Organizations involved in Unix-based computing may need to integrate applications from that platform into their PCs and workstations. The X Windows system, through OpenWindows and Motif implementations, offers a graphical windowing environment that is widely implemented in Unix-based systems. But, to run X Windows applications on a PC, you'll need an X Server. X Windows implementations for non-Unix systems were marketed as separate packages or through enhanced (in other words, more expensive) versions of TCP/IP network software.

Web Browsers: The Killer App The Web browser strives to be the all-in-one information access tool and is today's TCP/IP killer application. In previous generations of TCP/IP network software, vendors placed great emph asis on the multitude of applications and utilities packaged together, but today, business computing has converged on the developme nt of intranets where data from diverse databases and applications are distributed through Web servers.

Natively and through add-ins, browsers present text, graphics, sound and motion. The Web browser also has subsumed the functions of the gopher client, news reader and mail client, Internet Relay Chat (IRC) client and FTP utility. Through Common Gateway Interface (CGI) and other middleware gateways, users with Web browsers search, retrieve and update information in databases and other applications.

For many organizations, a built-in TCP/IP stack and Web browser will meet all of their needs, though some users may need a few traditional TCP/IP utilities. In many cases, only application developers and network administrators require the full complement of TCP/IP network utilities.

Client/Server Applications The last decade has seen the steady migration from host-based computing to client/server applications. Many organizations have developed custom applications or have implemented off-the-shelf sy stems that require a TCP/IP stack on the client workstation, even though they may not use standard TCP/IP utilities and applications. Clients that operate through a GUI have usurped a previous generation of software applications that relied on terminal-based interfaces.

Client/server applications often use nonconventional TCP sockets and may have other quirks that demand a very cleanly implemented TCP/IP kernel. If your organization's environment relies on a TCP/IP-based client, make sure that the kernel you select for your workstations is fully compatible.

Dial-Up Issues Mobile computing usually involves the need for dial-in access to the corporate network or to the Internet. TCP/IP software may be used on a local network, or it may rely on dial-up access via a modem. It is especially useful for notebook computers to be able to operate in either environment.

That' s not all. Can you easily switch between network and dial-up access? Can you do both simultaneously? For example, you shou ld be able to connect to other computers in your home office via a LAN and be able to dial into the network simultaneously. Does the software support Point-to-Point Protocol (PPP) or Serial Line IP (SLIP) access via a modem? There's no standard way for connecting to and logging into remote networks. Whether it's done through an Internet service provider (ISP) or a remote connection to the organization's internal network, some set of commands must be negotiated to authorize the user and initialize the PPP or SLIP connection. Most TCP/IP packages let you automate this process through a scripting language. You should carefully consider the range of modem types and communications speeds supported in the package before you buy anything.

File and Print Services NFS lets users access file systems on a remote server as if it were local. Many organizations use NFS for distributed file services rather than alternatives such as Novell NetWare or Microsoft Windows NT. NFS' differentiating factors include m anagement of user authentication and security, performance and integration of directory services (NIS, NIS+ or X.500). Find out if the TCP/IP stack includes only the client side, which lets the user mount file systems from remote servers, or if it also includes an NFS server, which lets users export their directories for other users.

Andrew File System (AFS) and Distributed File System (DFS) offer advanced capabilities over NFS. Security and performance are the two main issues of concern. NFS has earned a reputation for having weak security, while AFS and DFS use Kerberos--a ticket-based authentication system--to lock down access. It's also important to note that NFS implementations that operate via a WinSock interface generally offer poorer performance than those that are implemented in the kernel.

Marshall Breeding is the technology analyst for the Heard Library at Vanderbilt Un iversity. He can be reached at breeding@library.vanderbilt.edu.