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REVIEWSTake An Internet Tour Without Speaking The Language: IPX-To-IP Gatewaysby Greg Shipley |
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With the mass exodus to the Internet, many network administrators find themselves compelled to support yet another protocol across their LANs: TCP/IP. This challenge prompts administration challenges in the form of address assignments, router programming, new protocol bindings and multiple protocol stacks on the workstations, to name just a few. Just getting a network and its workstations to "speak" TCP/IP can be quite a task, not to mention worrying about security, monitoring and workstation support. IPX-to-IP gateways en able administrators to offer the wonders of the Internet to their Microsoft Windows users without having to support TCP/IP across the LAN or WAN. Using an existing IPX protocol stack, with minimal changes to the workstations, end users can be up and browsing in no time. Sound too good to be true? What's the catch? The truth is, many of these gateway products have been around for a while but only now are starting to mature. We took eight of the industry's IPX gateway offerings and put them through their paces, taking into account not only ease of installation and management, but a lso efficiency, price, compatibility and robustness. There are three primary benefits to using IPX gateway technology. The first is ease of migration. There are no TCP/IP stacks to be loaded, just minimal client software installations. The second is security. Because IP services are not loaded on the workstations, the chances of an unsuspecting user opening a security hole are eliminated. Also, if the IPX-to-IP gateway is the only computer on the network speaking TCP/IP, you have a single point to defend. The third benefit is control and centralized management. Because all access is going through one central point, the ability to easily monitor and control usage increases dramatically. In a pure TCP/IP environment, traffic is forwarded by a routing device. With IPX-to-IP gateways, all Internet-related traffic passes through the gateway, and many gateways allow administrators to easily log, filter and monitor traffic by using an assortment of included tools. A Look Under the Hood In a standard Internet scenario, when you launch a WinSock-compliant application (a Web browser, for example), it accesses lower-level protocols through calls to the WINSOCK.DLL file. Communications to the lower layers pass through the WinSock driver. IPX-to-IP-gateway technologies take advantage of this pathway by replacing the WINSOCK.DLL file with their own drivers. This enables the replacement WinSo ck to intercept requests for IP services and forward them to the gateway server via the IPX protocol. Once the IPX packet is received by the gateway, it converts the request and forwards the packet using the IP protocol. The IPX-to-IP gateway keeps track of both the IPX sessions and the IP sessions using the source and destination port addresses. Each IP session will be using a unique set of port numbers, and each IPX session will have its o wn address. The gateway simply has to perform protocol translation and keep track of who is talking to whom, based on known addresses. How We Ran the Tests Evaluating eight products across five different operating systems was no easy task. It becomes even more difficult when one has to keep things "fair." So, in the interest of keeping results as unbiased as possible, we ran our tests using the same workstations and server for each product. The server was a Pentium 120 with 16 MB of RAM and two 3Com 5390 NICs. For the w orkstations, we used an assortment of 486 and Pentium PCs running Windows for Workgroups 3.11, Windows NT and Windows95. The operating systems for the workstations as well as the server were wiped clean and reinstalled for each product. We configured the server with two NICs: One was attached to the live Internet segment, and the other was attached to the IPX-based LAN. The only exception to this was the Instant Internet product, which is a standalone turnkey solution. It did, however, ship with two Ethernet NICs that we used in the same manner. On the workstation side, when applicable, we tested any applications that were shipped with the gateway product. But we didn't stop there. We tested the gateways using an assortment of external applications including FTP clients, telnet clients and several Web browsers. If the replacement WinSocks are truly WinSock 1.1-compliant, they should work with all WinSock 1.1-compliant applications. Period. After much consideration, the contest between Quarterdeck Corp.'s IWare InternetSuite and Performance Technology's Instant Internet was too close to call. Although they take somewhat of a different approach--one is a turnkey solution while the other is a NetWare Loadable Module (NLM)--both offer a wealth of options with a very minimal amount of effort required by the installer. Both clearly stood apart from their competitors, excelling in manageability, ease of use and, most important, stability. Final ly, the pair offer something any burdened network administrator can appreciate: simplicity on the client side. They install a minimal amount of files on the workstation with little or no changes to configuration files. |
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Updated September 9, 1996
