Expected Network Problems
| UO Computing Center Microcomputer Services |
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MacTCP Based
Macs Expected Network Problems |
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Summary of this Document & Our Recommendations This document is in response to network problems that we experienced at the University of Oregon on 1/11/00, 1/12/00, and 1/26/00. The only machines affected were Macintosh computers that still use the MacTCP (or "Classic") style of network software. These machines were not able to access off-campus Internet sites during these periods. This problem lead Microcomputer Services and Network Services to research what was happening and to ask Apple for a formal response as to how the issue should be resolved. The bottom line is that the problem is a direct result of the MacTCP software not fully supporting features in the TCP/IP protocol. This is the protocol that network applications such as Netscape, Telnet, E-mail programs, FTC, News, etc. use to access the Internet. There are two fixes to this problem. One option (which is not recommended or supported) is to install a third party patch to MacTCP. The second option is to upgrade your Mac to run Apple Open Transport network software. This document discusses in detail the nature of the original problem, what MacTCP and Open Transport are, what Mac OS version to run, how to upgrade, how much RAM is needed, and possible problems as you do this. We present all this information to allow support professionals and end users to come to their own conclusions and to help them along the way. The final recommendations from Apple and Microcomputer Services are as follows:
Read on for a more complete discussion of what all of this means, including tables that summarize some of the RAM requirements for Mac OS versions with MacTCP and Open Transport installed. Index of Topics
What is MacTCP? [Return to Top] MacTCP stands for "Macintosh Transmission Control Protocol." The MacTCP Control Panel and associated software allow older style Macs to use the TCP/IP network protocol. This is the protocol that is used to transmit data on the Internet, and support of this protocol is required for any machine that wants to use Internet applications such as the web, e-mail, telnet, FTP, news, etc. What are the Problems with MacTCP? [Return to Top] MacTCP was created by Apple as an addition to their Macintosh Operating System before the Internet and TCP/IP had become the dominant network force they are today. As an additional piece of software this means that MacTCP was not as tightly integrated with the Macintosh Operating System as later products, such as Open Transport. Along with this, MacTCP does not fully support all aspects of the TCP/IP protocol and it has some implementation problems that are beginning to manifest themselves with time. As an example, during the second week of January, 2000, one of the primary companies that provides the UO with network connectivity decided to turn on a feature in the TCP/IP protocol called "Type of Service." This allows our provider to meter traffic coming in and out of the UO and other sites that use this provider (they are called NERO). Using this feature of TCP/IP is completely legitimate and is part of the TCP/IP protocol specifications. Unfortunately the MacTCP implementation does not deal with the Type of Service feature correctly. As soon as this feature is turned on any data that has the Type of Service setting included is rejected by any Mac receiving this data. What our Macintosh users at the UO saw, mainly, was that they suddenly could not access web sites off the UO campus. For those who access e-mail off campus, telnet to machines off campus, etc. these services were broken as well on Macs using MacTCP. For the moment, our provider, NERO, has agreed to artificially turn off this feature for all data that comes into the UO through their service. This actually causes considerable overhead on their hardware, slows down network traffic, and is not a standard way of doing business. The Type of Service feature will eventually be required for uses such as phone calls made over the Internet (this is known as Voice over IP, or VOIP), possibly some forms of video, and other services we may not have even thought of! The bottom line is that the Type of Service feature will be turned on at the UO at some point in the future. When this happens all older Macs will no longer be able to access various network resources. At this time Network Services has been able to give the UO campus community until 2001 to take care of this issue. If your Mac uses MacTCP it should be upgraded or replaced by January 1, 2001 so that it can run Open Transport instead. A Few More Words on MacTCP Issues [Return to Top] Microcomputer Services has been in contact with Apple Support Professional services to verify that Apple will not issue patches to MacTCP to resolve this problem and future problems. Apple's stand, and this is not surprising, is that MacTCP was last upgraded by them in 1994 and is now a dead product. No further Apple certified changes are upgrades are forthcoming. Instead, Apple recommends that all their customers upgrade to Open Transport as soon as possible. With this in mind, there is an interim measure that can be taken by those users who cannot upgrade to Open Transport. There is an unsupported fix to MacTCP that we make available that resolves the Type of Service problem. There are, however, several problems with using this fix. These include:
As may be obvious, we strongly recommend upgrading all Macs using MacTCP to Open Transport compatible Macs as soon as possible. How Can I Tell if I'm Using MacTCP? [Return to Top] If you can access the Internet on your Macintosh computer, then go to the Apple menu, choose Control Panel, and look for a Control Panel called MacTCP. If it exists, you are using MacTCP. Note, if you have a Control Panel called TCP/IP, then you are using Open Transport. If you want to know what version of MacTCP you are using it should be listed in the lower left corner of the MacTCP Control Panel when you first open it. What is Open Transport? [Return to Top] Open Transport is Apple's more fully integrated network component with the Macintosh Operating System (or the "Mac OS"). Apple considers Open Transport to bring a "...workstation-class implementation of TCP/IP protocols to the Mac OS." Apple supports Open Transport and has written it (as of version 1.1.1) to correctly support the full TCP/IP protocol and network environments such as exist at the University of Oregon. How Can I Tell if I'm Using Open Transport? [Return to Top] Go to your Apple menu and choose Control Panels. If you see a Control Panel called TCP/IP and/or AppleTalk, then you are running Open Transport. If you wish to see what version of Open Transport you are using open the TCP/IP Control Panel, go to the Edit menu, choose "User mode...", click on the Advanced button, then click OK. Your TCP/IP window will now change and you will see an Info button. Click the Info button and the version of Open Transport will be displayed. What are the Minimum Requirements for Open Transport? [Return to Top] This is an open ended question in some ways. Microcomputer Services recommends that users either upgrade to Mac OS version 7.6.1, which has Open Transport built-in, or at the very minimum upgrade to Mac OS version 7.5.5 and install Open Transport version 1.1.2. Here is a list of how much RAM is required to run Open Transport version 1.1.2 on a few different versions of the Mac OS. A list with data for using MacTCP version 2.0.6, 2.1.1, Open Transport 1.1.1, and Open Transport version 1.1.2 is presented little later in this document in Table 2. Note that these numbers are not exact. They were obtained by doing a clean system install on a Mac Quadra 650. Your numbers will vary depending on the Apple hardware in use, but these numbers will be close to what you should see. Also note, we did not install Open Doc or QuickDraw GX under Mac OS 7.6.x, and we do not recommend that anyone else install these products either. Users on PowerMac computers may see considerably higher RAM requirements due to differences in Mac OS software installs. Table 1: Macintoshes that are Unable to Run MacOS 7.6 or Later
by running a network application. Notes About Mac OS Upgrades and Open
Transport Upgrades There are multiple nagging points that you will have to deal with as you go between Mac OS versions and Open Transport.
One of the critical issues for many users is if their previously installed software will still run correctly after installing a new version of the Macintosh Operating System. The older the software, the less likely it is to run as you upgrade Mac OS versions. This is something to be aware of and investigate before making major upgrades. Generally minor upgrades (i.e. 7.5.3 to 7.5.5) don't cause problems, but larger upgrades (i.e. 7.1 to 7.6.1) may cause older software to fail. As you upgrade watch out for third party Extensions, Control Panels, font management software, menu bar modifiers, and screen savers. These types of software are the most common reasons why users experience problems after upgrading their Mac System software. Whenever possible, try removing this software first and check for upgraded versions that you can install after you complete your upgrade.
WARNING: if you are upgrading from any version of Mac OS 7.5.1, and earlier, to any Mac OS version 7.5.2, and above, please read the following. If you don't you can lose all the data on your Mac's hard drive! Starting with Mac OS 7.5.2 Apple changed the way their low level SCSI drivers work. What this means is if you own a Macintosh computer with an original Apple hard drive and the hard drive is a SCSI drive it is absolutely critical that you update the SCSI drivers on your drive before you upgrade to Mac OS version 7.5.2, or higher. Also note, Microcomputer Services does not make Mac OS version 7.5.2 available due to multiple, serious problems with this version of the Mac OS. Instead we make version 7.5.3 available. In both cases the SCSI driver issue still applies. To update your SCSI driver on an Apple-branded SCSI drive you should go to the Disk Tools, or Utilities folder for the Mac OS version you plan to install. You should then run the program Apple HD SC Setup, choose your main hard drive as the SCSI device selected, and then Update the drive. Don't Initialize the drive as this will format the drive and cause you to lose any data that is not backed up. Apple officially recommends that you backup any data before using the Update feature of the Apple HD SC Setup tool - we recommend this as well, but, so far, have not run into problems using the Update feature of Apple HD SC Setup.
You can install Open Transport 1.1.1 directly from the CC Public Domain AppleShare server by opening the following folders:
You can then choose to run the installer directly from the Net Install folder, or you can make disk images of the installer from the Disk Images folder. You must install Open Transport 1.1.1 before you can run the Open Transport 1.1.2 installer. Unfortunately there is no standalone Open Transport installer for version 1.1.2. You can find the Open Transport 1.1.2 installer by opening the following folders on CC Public Domain
There are many versions of Open Transport. Version prior to 1.1.1 had problems correctly using BootP and DHCP servers. This becomes important because these older versions required users to hard code network values in the TCP/IP Control Panel. This is a recipe for increased support headaches since these values may change and it requires more work on the user's end. Versions 1.0.8 and earlier had serious problems for users attempting to use dialin connections for TCP/IP network connectivity. Version 1.1.2 of Open Transport runs on all Mac OS version 7.1 to 7.6.1. Mac OS 7.6 was the first Mac OS version to only install Open Transport. No support for MacTCP exists in Mac OS 7.6 and above. Starting with Mac OS 8.0 the Open Transport version you run is based on the Mac OS version you are using. There are some minor Open Transport updates that are Mac OS specific (1.3. to 1.3.1 and version 2.6). Thus, there is no concept of a standalone Open Transport installer for any version above 1.1.2. For instance, there is no Open Transport 2.x installer that will install on multiple Mac OS versions. We recommend that all users moving from MacTCP to Open Transport update to Open Transport 1.1.2, or above, since the first troubleshooting step that will be required if there are problems with Open Transport version 1.1.1 machines will be to update to version 1.1.2. The memory requirement for Open Transport version 1.1.1 and 1.1.2 are almost identical. Finally, Open Transport version 1.1.2 fixes some problems for user who dialin that may be useful.
If you install Mac OS 7.5 you will receive a message recommending that you install both these products once the installation finishes. Microcomputer Services strongly recommends against this. Both products are dead technologies, particularly PowerTalk, and they both use large amounts of RAM. They are not necessary to function on the University of Oregon network.
If you install the System 7.5 Update 2.0 this will upgrade your Mac OS version to 7.5.3. If you have already installed Open Transport 1.1.2 this update will downgrade your Open Transport version. You will need to reinstall Open Transport 1.1.2 after running the System 7.5. Update 2.0. This downgrade of your Open Transport software does not appear to cause serious problems, but it is something to be aware of.
If you install Mac OS 7.6 you can optionally install QuickDraw GX and/or OpenDoc. Microcomputer Services strongly recommends against this. Both products are dead technologies, and they both use large amounts of RAM. They are not necessary to function on the University of Oregon network. Other Issues to Watch For and Detailed Memory
Requirements It is interesting to note that older Macs can run Open Transport, but there are some potential future headaches if you are using a Mac running, say, System 7.1 and Open Transport. These issues include:
Finally, remember that the MacTCP 2.1 patch requires 250 to 300K more of RAM. Please see our detailed table below of Mac OS versions and how much RAM is required to use MacTCP 2.0.6, 2.1, Open Transport 1.1.1, and Open Transport 1.1.2 under each version. This may help you to decide on your next step depending on what hardware you have or are upgrading. Please read our recommendations for minimum system versions and hardware at both the start and end of this document. As mentioned above Table 2, these numbers are not exact. They were obtained by doing a clean system install on a Mac Quadra 650. Your numbers will vary depending on the Apple hardware in use, but these numbers will be close to what you should see. Also note, we did not install Open Doc or QuickDraw GX under Mac OS 7.6.x, and we do not recommend that anyone else install these products either. Finally, numbers vary as the Mac OS is running, so the RAM used should be considered within some small percentage of typical performance we might see. Table 3: Mac OS Versions and RAM
Requirements for OT and MacTCP
How do I Configure Open Transport? [Return to Top] Generally you don't need to. There is one quirk, however, to watch for. After installing Open Transport, you will need to go to the Apple menu, choose Control Panels, and then choose to open the TCP/IP Control Panel. You will be asked if you want to make TCP/IP Active after closing the Control Panel. Say yes to this. Open the Control Panel and close it. Open Transport (specifically the TCP/IP stack) is now active. If you skip this step your TCP/IP applications (Netscape, Internet Explorer, telnet, Eudora, e-mail, Fetch, news, etc.) will fail to work correctly. In some cases your TCP/IP stack may fail to receive all the information you need to make a successful connection. We have seen this more commonly with dialup connections. Here are all the settings that you can manually configure in the TCP/IP Control Panel for the University of Oregon if you are having problems. If possible, we recommend not entering this information as you must change it if you move your Mac to another network, or in the event any of this were to change in the future (we try not to do this, but things change). First, Open the TCP/IP Control Panel. Go to the Edit menu, choose "User mode...", click the Advanced button, and then click OK. Now you can enter in this information. The tables below are for on-campus users using ethernet,
and off-campus users with the various dial-in packages that are available
for Open Transport enabled Macs.
OK, SO I Don't Want Open Transport.
Where's the MacTCP Patch? If you decide that you cannot upgrade to Open Transport (probably due to memory limitations) you can use the MacTCP version 2.1 patch that was created by Glen Anderson. You can see his MacTCP patches page at: As you may have noted, Glen Anderson is not Apple Computer, Incorporated. So, while we greatly appreciate the fact that this patch exists, and appears to solve the problem we see on the University of Oregon network when the "Type of Services" feature is turned on in the TCP/IP protocol, the patch itself is completely unsupported. As of February 1, 2000 the last time that the MacTCP patch pages had been updated was August 4, 1998. What this means is that if future problems arise that the MacTCP 2.1 patch does not solve, then there is no available support from Apple or anyone else. Also, while we have tested this patch to the best of our (Microcomputer and Network Services) ability, it is impossible to test this on a large scale. It's possible that there are unknown issues with this patch that will surface if many people start to install it.
OK, with that long disclaimer in place, you can get the patch from CC Public Domain by opening the following folders:
We recommend just copying over the MacTCP Control Panel and MacTCP Prep files located in the subfolder, "MacTCP 2.1 - already patched" - The MacTCP Prep file should go into the top level of your System folder. You can throw away the MacTCP Prep and MacTCP DNR files in the System folder before copying this file over. You should copy the file MacTCP to the Control Panels folder in your System folder. Remember, this patch requires System 7 to 7.5.5, and a 68030, or higher, Mac to run. Conclusion [Return to Top] Microcomputer Services conclusion is that after investigating this matter deeply and creating this document it becomes apparent that support costs for older Macs are likely to increase. If you read this whole document, and have actually made it to this conclusion, then you may be ready to buy that new Mac any way you can to get to a modern version of the Mac OS so that you don't have to deal with issues like this. We recommend (as of February 2000, this is a moving target!) as a minimum a PowerMac with 64+ MB of RAM and Mac OS 8.x. A number of new programs have problems running on Mac OS 8.0 and want 8.1 or 8.5, but in most cases our minimum recommendation should work for most users. Note that the University of Oregon has the legal right to give you Mac OS version 8.1 (if you are a current UO student, faculty, or staff member) for free. We are aware of financial constraints, time to upgrade, costs of learning a new system and programs, etc. That is why we are trying to present this information as far in advance as possible. We hope that this will give people plenty of time to secure funds and prepare for these types of upgrades. Further Questions? [Return to Top] Current University of Oregon students, faculty or staff
feel free to contact Microcomputer Services directly. You can send us
e-mail to microhelp@oregon.uoregon.edu,
see our main web site at http://micro.uoregon.edu,
stop by our consulting offices in Room 202 of the Computing Center, or
call us at (541) 346-4412 anytime between 9am and 5pm, Monday through
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