Macintosh PPP Overview (Part 1)
As an increasing number of people access the Internet via a Mac and a modem, the software they use to connect becomes increasingly important. The connection software combination of MacTCP and either a SLIP or PPP program has become popular, because it gives people full TCP-based Internet connections that enable them to run programs like Anarchie, Netscape, NewsWatcher, and Eudora. However, setting up such connections has become confusing: many new versions of SLIP and PPP programs have been released in recent months, and though Open Transport has replaced MacTCP for users of the PCI Power Macs (requiring changes to the connection software), a number of compatibility issues have resulted in a flurry of maintenance releases.
How They Work — SLIP and PPP are two protocols, or methods, of making an Internet connection with a modem over the phone line. Generally speaking, a SLIP or PPP program provides a temporary, low-speed Internet connection through your modem. Imagine that you have no water service to your house, and the only way to take a shower is to run a garden hose out to the water main in the street. That’s similar to what SLIP and PPP programs do for you, in conjunction with a modem: they establish a relatively low-speed (garden hoses don’t carry that much water, and SLIP/PPP connections are limited by the speed of your modem), temporary (when you’re done with your shower, you bring the hose back in) connection to the Internet.
The PPP protocol has slightly better technical specifications than SLIP, and in my experience can sometimes be slightly faster than SLIP. However, in the real world, the main difference between SLIP and PPP (assuming your Internet provider supports both, as mine does) lies in the programs that make each protocol run on your Macintosh. In this respect, PPP has a significant advantage over SLIP: there are several different freeware options for running PPP on the Mac (as opposed to InterSLIP, the lone free SLIP implementation, written by InterCon Systems), as well as a couple of commercial options. There are also a number of different pieces of add-on software that enhance the freeware PPP programs.
ftp://mirror.aol.com/pub/info-mac/comm/tcp/ inter-slip-installer-101.hqx
PPP and Open Transport — Open Transport is Apple’s new networking architecture. Eventually, it’s supposed to replace all of Apple’s low-level networking code on all Macintoshes; right now, it runs only in a preliminary release on the new PCI-based Power Macs (the 7200, 7500, 8500, and 9500).
One of the teething problems PCI Mac owners have with the preliminary Open Transport release is a series of compatibility problems with Internet software. In particular, InterSLIP and most of the basic PPP programs don’t work with Open Transport. The only dial-up Internet programs known to work with Open Transport are a pair of MacPPP derivatives – MacPPP 2.1.2SD and FreePPP 1.0.2 – and the commercial programs InterPPP II and MacSLIP. Apple is supposed to provide PPP software as part of Open Transport, but it isn’t included in the preliminary release.
Please note that I haven’t used any of the PCI Macs yet. The information I have on Open Transport has been gleaned from posts to various Usenet newsgroups.
MacPPP, the Original and Derivatives — The first widely-used Macintosh PPP software was MacPPP, written by people at Merit Network and the University of Michigan, and released free to the public. MacPPP went through several versions before reaching its current release, 2.0.1, in 1993. Since then, several people have obtained the source code to MacPPP and have written derivative versions; unfortunately, each derivative usually had just one or two added features, and you couldn’t run two versions at once to get both sets of features. Two different groups have worked on collecting the best features from all of these versions into a single coherent release, giving a growth path for the future. [See "The Future of PPP Projects" in next week’s article. -Geoff]
Here is a rundown of the MacPPP-based programs that will establish a dial-up Internet connection using PPP. All of the programs described below are available on the Info-Mac software archive, in the MacTCP software directory:
ftp://mirrors.aol.com/pub/info-mac/comm/tcp/
If I’ve used a particular piece of PPP software, I’ll give my opinions on how well it works. However, I haven’t used everything, and what I have tested has only been used on my old PowerBook 170, my new PowerBook 5300, my IIci at home, or an 840AV at work. I can’t guarantee how well these programs will work on your system.
MacPPP 2.0.1 is the last official University of Michigan release. Its interface is clunky, it’s a bare-bones program with relatively few features, it hasn’t been officially updated in two years – but it’s the standard. Several people have released PPP versions based on MacPPP 2.0.1, and many others have written add-on software that works with it, making it the reference version everything else is compared to. Unfortunately, it does not work with Open Transport. If you’re not using Open Transport, MacPPP 2.0.1 is still the safest version to use before trying any of the derivative versions.
MacPPP 2.0.1cm4, by Cliff McCollum, adds three main features to the basic MacPPP 2.0.1 release:
- The basic MacPPP has minimal support for entering your user name and password as you sign on. If your PPP server supports PAP authentication, you can enter your password in MacPPP’s Authentication dialog; otherwise, you must put your user name and password into your connect script. MacPPP 2.0.1cm4 adds a pair of tags – $USERID$ and $PASSWORD$ – that allow your connect script to ask for that information when you sign on.
- Some internal PowerBook modems wake up slowly from the power saving sleep mode; 2.0.1cm4 adds a slight delay that’s supposed to fix the problem. (I haven’t tested this in 2.0.1cm4.)
- The original MacPPP 2.0.1 used a modal dialog box to display the connection status, which kept you from doing anything while MacPPP was dialing. 2.0.1cm4 allows you to start dialing and switch to another application, though the program that you started dialing from is suspended until dialing is completed.
MacPPP 2.1.2SD is another Merit MacPPP derivative, written by Steve Dagley (hence the SD initials at the end of the name). Its original purpose was to add support for high-speed serial connections on Macs with GeoPorts, and it was later the first PPP version to support Open Transport. Several people have contributed to it since its initial release. Here are some of the more significant features:
- Allows serial-port-to-modem connections of 115 Kbps and 230 Kbps for Macs with GeoPort technology (the 660AV/840AV, and most Power Macs).
- Supports Open Transport on the PCI Macs.
- Several fixes to provide better support for timing-sensitive modems, by John Stephen.
- Includes a fix for PowerBook modems that are slow to wake up.
- Support for PSI’s ISDN service, also by John Stephen.
- Improvements to the Terminal window for manual connections.
- Displays the connect speed in the PPP status box.
I use MacPPP 2.1.2SD on my old PowerBook 170, and it seemed to be more stable (and cause fewer problems with the internal modem) than MacPPP 2.2.0a on the same machine. With the release of FreePPP 1.0.2, also by Steve Dagley and based on the same code, MacPPP 2.1.2SD is technically obsolete; however, I’d probably keep it around a little while longer until we see how stable FreePPP turns out to be. [For more details on FreePPP, see next week’s continuation of this article. -Geoff]
MacPPP 2.0.2 (YA 1.0) — Also called MacPPP 2.0.1mlb, 2.0.2 (YA 1.0) was created by Mason Bliss to disable MacPPP’s automatic connection feature. Although FreePPP includes this option, Bliss had problems with FreePPP’s stability, so he released this version. It’s distributed as a patching program for 2.0.1, so you need an unmodified copy of 2.0.1 to use 2.0.2 (YA 1.0).
Other versions of MacPPP have been created, but 2.0.1cm4, 2.1.2SD and 2.0.2 (YA 1.0) are the only "first derivative" versions still in circulation at Info-Mac.
Stay Tuned — Next week, I’ll cover current freeware PPP projects as well as commercial PPP implementations. Please note that this article is based on information from my Web page on Macintosh PPP software. I’ll keep updating this page with new information on PPP programs as I find it.