Mac TCP Cookbook

MACTCP COOKBOOK: CONSTRUCTING NETWORK- The Macintosh is now a full-fledged player in the world of TCP/IP AWARE networking. MacTCP, an implementation of TCP/IP for the Macintosh, lets applications take advantage of a protocol suite that APPLICATIONS is used extensively by many makes of computers. This article attempts to demystify the process of MacTCP programming and provides a library of calls that can be used easily by anyone familiar with Macintosh programming. TCP/IP, which stands forTransmission Control Protocol/Internet Protocol,was developed by the U.S. Department of Defense Advanced Research Products Agency (DARPA) and used initially on the ARPANET, a national research network created by DARPA in the late 1960s. Although the ARPANET no longer exists, the TCP/IP protocols are used on many large-scale networks. Many of these networks are interconnected and are known collectively as the Internet. The TCP/IP protocol stack, shown in Figure 1, is composed of several layers. At the lowest layer, the Internet Protocol (IP) handles transmitting packets of information from one host to another. Above this network level, TCP/IP provides two transport layer protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). TCP provides reliable connection-based service, while UDP is not connection based. The MacTCP® driver gives the programmer interfaces to TCP and UDP, but not to the lower- STEVE FALKENBURG level IP. This article deals only with TCP programming. For information on MacTCP UDP programming, consult theMacTCP Programmer’s Guide. Several application-level protocols use TCP to provide user-level service. The Simple Mail Transfer Protocol (SMTP) is used to send electronic mail, the Network News Transfer Protocol (NNTP) is used to transfer and post news, the File Transfer Protocol (FTP) is used to transfer files between machines, and the Finger protocol is used to retrieve user information. MacTCP does not include programming interfaces or implementations for any of these application-level protocols. 46 STEVE FALKENBURG j…