The first thing I want to say right off is that although I recommend PPP over SLIP, in practice the two methods of connecting to the Internet work almost identically. Performance is similar, and once SLIP or PPP is set up, ease of use is equally similar. If you don't have access to a PPP account or for some reason you simply can't get MacPPP to work, there's nothing wrong with using InterSLIP or one of the other implementations of SLIP and a SLIP account.
If you skipped chapter 18, "PPP," you may wish to go back and read the first parts to get a sense of how SLIP and PPP differ, but the short answer is that although they're functionally identical, they're not interchangeable. So, if you're using a PPP account, you can't use InterSLIP or VersaTerm SLIP with it. They simply won't work, and the reverse is true as well.
Note: You may also hear about CSLIP accounts. CSLIP stands for Compressed SLIP, and it's generally handled by an option in the SLIP program. You don't need a different SLIP software to use a CSLIP account.CSLIP might also be referred to as SLIP using Van Jacobsen header compression or RFC 1144 TCP header compression. It does not compress the data being transferred, it just reduces the amount of overhead information that needs to be transferred over the modem.
SLIP provides an Internet connection for people who connect via modem. If you have a network, either Ethernet or LocalTalk, connected to the Internet, you don't need SLIP.
The easiest way to understand SLIP is to pretend that you don't have water service inside your house. Every time you want to take a shower, you must run a garden hose out to the water hookup outside, take your shower, and then reel the hose back in. That's exactly what SLIP does -- it establishes a temporary, low-speed connection to the Internet. You must create that connection before you can run programs such as MacWeb and Fetch.
Note: Although some implementations of SLIP enable you to launch a MacTCP-based program without connecting first (the SLIP software sees what's up and then establishes the connection), I've found that these autoconnect features can be flaky. If you can use one, great, but if it doesn't work reliably, connect manually first.
SLIP for the Macintosh currently has three different implementations (not counting programs that support SLIP internally, because they're of no use if you want to use another program that doesn't support SLIP internally). Two are commercial, MacSLIP from Hyde Park Software and VersaTerm SLIP from Synergy Software. The third comes from InterCon Systems, a company that has released numerous Internet products, some of which support SLIP internally. InterCon has released this last SLIP, called InterSLIP, as freeware on the Internet, and has graciously allowed me to include it on the disk that comes with this book.
In this chapter, I concentrate on InterSLIP because the other SLIP implementations, being commercial, come with printed documentation and support, and because, in many ways, they are all similar. I'll point out the few differences that I've encountered and comment about why you might want to use one over another.
When it comes time for you to get a SLIP account, you should check back in chapter 11, "Choosing a Connection," for information on how to pick an Internet access provider. Once you decide on a provider, you need certain information from that provider to configure InterSLIP or other SLIP software. For convenience, I list the most common pieces of information you need in table 19.1.
Table 19.1: SLIP Information
Item Question
Phone Number What number do I call to connect to the server?
Login Name What is my SLIP account login name?
(This name can be different from your userid
or machine name.)
Password What password should I provide when logging in?
MTU What is the maximum transmission unit size?
(1,006 seems to be the standard MTU for SLIP;
I've heard of using 296 for CSLIP.)
Header Compression Should I use RFC 1144 TCP Header Compression
(also known as CSLIP)?
Login Procedure What should I expect to receive from your host
machine and how should my Mac respond when
logging in?
IP Address What is my IP number (if a manually addressed
account)?
Gateway Address What is my gateway IP number (if a manually
addressed account)?
Domain Name Server What is the IP number of my primary domain
name server?
Again, it's probably easiest to use the worksheet in the back of this book for recording all of this information. I'll cover InterSLIP first and then look at other SLIP software and add-ons.
InterCon's InterSLIP is one of the most popular pieces of software among the Macintosh Internet crowd because it is freeware that offers functionality equivalent to commercial programs. That's a good way to make friends. InterCon has graciously allowed me to include it on the disk that comes with this book.
Note: My examples and screen shots in this section apply specifically to configuring my modem, a Telebit WorldBlazer, with a manually addressed SLIP account. Your settings will be different; I guarantee it. For a step-by-step walk-through of how to install InterSLIP for a server-addressed account with Northwest Nexus, check out chapter 29, "Step-by-Step Internet."
Installing InterSLIP requires placing an extension called InterSLIP in your Extensions folder. If you drag it onto the System Folder icon, System 7 places InterSLIP in the correct location. A control panel called InterSLIP Control is also available (and generally installed by default), but in fact it's entirely unnecessary for System 7 users; it is only required for use with System 6. The application called InterSLIP Setup can live anywhere on your hard disk, but it may be a good idea to put it or an alias to it in your Apple Menu Items folder for easy access. After you place those parts in the proper places, reboot your Mac. Make sure InterSLIP is selected in the MacTCP main window, and then proceed with configuring InterSLIP.
Note: On the disk in the back of the book, the ISKM Installer's custom options that include InterSLIP install all of the parts of InterSLIP in the proper places. Just as with MacTCP and MacPPP, I provide the detail here in case you install InterSLIP from some other source (such as an update) or merely want to know how the manual installation process works.
Although InterSLIP Setup and InterSLIP Control share similar interfaces and functions, you use InterSLIP Setup to configure your connection. InterSLIP Control enables you to select a configuration and connect and disconnect, but you must configure it from InterSLIP Setup (hence the name, I suppose) (see figure 19.1). Frankly, if you use System 7, I'd recommend throwing InterSLIP Control out. I haven't had it installed for months now, and it's made no difference at all.
Figure 19.1: InterSLIP Setup and InterSLIP Control.
To create a new configuration, launch InterSLIP Setup, and from the File menu choose New. InterSLIP Setup prompts you for a name with a dialog box; give your configuration a name (it doesn't matter what) and click on the OK button. Although InterSLIP Setup provides no way of deleting a configuration from within the program, configuration files are stored in an automatically created InterSLIP Folder within the Preferences folder. If you create a configuration you don't want to keep, throw out its file from this folder.
After you create the configuration, you must configure it for your particular modem and account. You need information from your system administrator to configure InterSLIP, so be prepared to give your provider a call if you didn't get it all when you signed up for the account. Double-click on the configuration you just created to bring up the configuration dialog (see figure 19.2).
Figure 19.2: InterSLIP configuration dialog.
Let's take it from the top left of the dialog. The serial port should generally be set to your Modem port, although you could attach a modem to your Printer port. If you use a PowerBook with an internal bus modem that connects directly to the CPU (such as the Apple Express Modem and the Global Village PowerPort/Mercury for the PowerBook 500 series and the PowerBook Duo), you get an Internal Modem choice, and the PowerBook 500 series may show a Printer-Modem Port choice. Although I don't have such a modem to test, I suspect that if you have a nonbus internal PowerBook modem, you should choose the Modem port, just as with MacPPP (also see the notes about bus modems in chapter 18, "PPP").
The Baud Rate setting is the rate at which your modem and your Mac communicate, which is why there is no setting for 14,400, since that's a speed at which the two modems communicate (and some modems cannot even accept a port speed of 14,400 or 28,800 bps). The speed that the Mac and the modem communicate should be set faster than the speed that the modems communicate to take advantage of modem compression capabilities.
Data Bits, Stop Bits, and Parity are almost always set as I have them here, to 8 data bits, 1 stop bit, and no parity, although I suppose it's possible that some providers are different. The Hardware Handshaking checkbox requires that you have a hardware handshaking cable, and if you have a fast modem, you should have one of those. I've heard that if you don't have a hardware handshaking cable but attempt to use that checkbox, it may cause InterSLIP to hang.
Turning the speaker on or off is up to you, although I generally recommend you leave it on until you have everything working for a few days. Then, when the modem screams start to irritate you, turn it off.
Note: Depending on your modem and your modem initialization string, InterSLIP sometimes seems to ignore the speaker checkbox. You can always override it by adding M0 to your initialization string to turn off the modem speaker.
The Dial Script pop-up menu defaults to Direct Connection, something I doubt most people have. The other built-in choice is Hayes-Compatible Modem, and I recommend you choose that option to start with. I certainly hope your modem is Hayes-compatible; you're likely to have trouble if it's not. Unfortunately, even if your modem claims it's Hayes-compatible, that doesn't inherently mean that it works with the Hayes-Compatible modem script in InterSLIP. Luckily, InterSLIP supports other modems through the use of dialing scripts written in the CCL (Connection Control Language). CCL scripts are primarily used with Apple Remote Access (ARA). You can find many dialing scripts (their names start with scr and generally include a modem name as well) in:
ftp://ftp.tidbits.com/pub/tidbits/tisk/tcp/
Note: Dialing scripts are text files that are very similar to ARA (Apple Remote Access) scripts. The only difference is that ARA turns off data compression and error correction, whereas those two settings should be on for an InterSLIP dialing script. Many modem vendors will send you an ARA script for your modem, if it wasn't included, and you can find many ARA scripts in:
ftp://ftp.tidbits.com/pub/tidbits/tisk/ara/
You can add dialing scripts to the Dialing folder inside the InterSLIP Folder inside the Preferences folder. To edit an ARA script, you may have to use Shift-Open in Word or Nisus's All Files option in its Catalog to be able to open the ARA script. These scripts are text-only, but they tend to come with a type and creator that prevents text editors from reading them. Make sure to save as text when you're done, though. Dialing scripts can be very important -- for some modems, they're even essential.
I've found that many dialing scripts have huge amounts of useless sections; Fred Morris has written a minimal dialing script that works well with many modems, assuming the modem initialization string you use is correct. I added redial capabilities to the script and included it on the disk so that the ISKM Installer installs it for InterSLIP by default. It's called Minimal Dialing Script, and aside from being able to redial, it's useful because it tends to be more effective at hanging up your modem when you click on the Disconnect button in InterSLIP, something the Hayes-Compatible Modem choice has trouble doing with some modems. Enough about the Dial Script menu; stick with Hayes-Compatible Modem or my Minimal Dialing Script, if you can.
Note: Considering how much technical support costs, the people at InterCon help you with InterSLIP only if you are also a registered user of one of their other programs. I think that arrangement is extremely fair because they've already provided a great service to the Internet community by releasing InterSLIP for free. So please, do not expect support from InterCon unless you purchase one of their other products.
The next three items, which control the dialing method, phone number, and modem initialization string, don't appear until you choose Hayes-Compatible Modem or another dialing script. I hope that when these items appear, it is relatively obvious how to fill them in. Most people have tone dialing these days (although the few people with pulse dialing would do well to check dialing scripts for ATDT commands and replace them with ATDP commands), and your system administrator should tell you the phone number when you get the account. The modem initialization string is a bit trickier, but most modern modems support something like AT&F1 for setting the factory default standard options. As you can see, my WorldBlazer goes all out on the &F parameters; I must use AT&F9, which turns on hardware handshaking for the Macintosh. Look in your modem manual or in another communications program that comes with settings for popular modems to figure out the most appropriate initialization string.
Note: I've also included a file containing many modem strings on the disk. The ISKM Installer has the information in the installer help text, and the file is installed in the InterSLIP 1.0.1 folder (not the InterSLIP Folder that lives in your Preferences folder). These modem strings are generally untested, but should either work or put you on the right track.
The most important thing I know of to watch for here is the hardware handshaking setting. Not only do you want to make sure your initialization string turns on hardware handshaking, but you also want to make sure that software handshaking, more commonly known as XON/XOFF, is turned off. If XON/XOFF is turned on in the modem initialization string or is part of the factory default settings (as it is for the Telebit QBlazer modem), InterSLIP almost certainly won't work right.
At the top right of the window is another pop-up menu labeled Gateway. It defaults to Direct Connection, but again, I think the other option, Simple UNIX/Telebit, is more commonly used. The Simple UNIX/Telebit script simply looks for the login prompt, sends your userid, looks for the password prompt, sends your password, and assumes there's nothing more to do before starting SLIP. Unfortunately, that's not always true.
Just as with dialing scripts, you can write your own gateway script in the Connection Control Language and place it in the Gateway Scripts folder in the InterSLIP Folder. Unfortunately, if you have a nonstandard gateway, you probably will have to write your own, although I've collected a few of them in:
ftp://ftp.tidbits.com/pub/tidbits/tisk/tcp/
(Look for "scr" in the beginning of the name, and the name of a provider, university, person, or server such as Annex or Cisco in the rest of the name.)
The gateway script is a conversation between your computer and your host computer as your computer tries to log in to the host. There's no telling what sort of prompts your host sends or what it requests, so again, I can't help much with specifics here. I strongly recommend that you work through the process manually using a terminal emulator to see what the host sends and what it expects back. Once you've done that, you stand a chance of converting that information into a gateway script. Also, ask your system administrator to advise you of any quirks in logging in.
Note: A few people need to use what's called a dialback system which, for security reasons, makes you log in normally, then hangs up and calls you back at a prespecified phone number. Although a truly hairy process, you could write a gateway script that, instead of just logging in, would log in, hang up the phone, set autoanswer, wait for a RING, answer the phone, wait for a CONNECT, and then proceed with the rest of the script. Nasty, but possible.
In general, you usually send a return, the host sends a login: prompt, you send your login name, the host provides a Password: prompt, you send your password, and then something else happens. For instance, if you use a server-addressed account, the gateway script must include some method of finding the IP number that the server assigns to you -- it usually appears after you send the password. I've included a gateway script that works with the Northwest Nexus server-addressed accounts, and I recommend that you use it as an example of how to write your own (not that it's a paragon of scripting virtue, but it does work).
Note: Many people ask where they can find more information on scripting in the CCL language that InterSLIP uses for both dialing and gateway scripts. Unfortunately, the best information available is in InterSLIP's documentation, so you've got it already. Maybe someone will write a CCL tutorial and post it on the nets. (Hint hint!)
If you have trouble making InterSLIP connect, you might also try a hack with which some people have reported success. Set InterSLIP to Direct Connection in both the Dial Script menu and the Gateway menu. Then, using a terminal emulator, dial your host machine, and at the point when SLIP starts on the host, click on InterSLIP's Connect button. It's a hack indeed (ordinarily you'd never use a terminal emulator to dial a SLIP account), but it might work while you figure out a gateway script.
Let's move on to the User name field in the InterSLIP configuration dialog. Most of the time, your system administrator assigns this name to you, along with a password, although you may get to pick them yourself. Your username may or may not be related to your machine name or your email address. It's simply the name you use to log in to your SLIP account. Make sure you enter your username in lowercase -- Unix is case-sensitive, so Adam is not the same account as adam, and your password won't work with a mixed-case username if it were created with a lowercase username.
I've checked the Prompt for password at connect time checkbox in the InterSLIP configuration dialog because publishing a screen shot of my password isn't a terribly clever thing to do in terms of security. However, if that checkbox isn't checked, you get another text field that holds your password. If you don't mind the security risk of having your password visible here, go ahead and enter it, being careful to enter it exactly as it was created. Passwords are always case sensitive, so make sure you match the case of each letter or else the host will reject it.
The next four items -- IP Address, Nameserver, checkbox for RFC 1144 TCP Header Compression, and MTU (Maximum Transmission Unit) Size -- require information from your provider. You can see the sorts of things I've put in, but your situation may be entirely different (and your IP Address and Nameserver certainly are). Again, if your provider tells you that you have a CSLIP account, make sure to check the TCP Header Compression checkbox. Even if the term CSLIP isn't mentioned, make sure to check with your administrator, because if the TCP Header Compression setting in InterSLIP doesn't match what your account has set, weird errors will result.
After you're all done, click on the OK button to save your changes. If you have more than one SLIP account on different hosts, you can create additional configuration files and switch between them in InterSLIP Setup by selecting the one you want before you click on the Connect button.
Clicking on the triangle in the upper left of the InterSLIP Setup window shrinks the window to display only the Connect and Disconnect buttons and the area that displays the connection status (see figure 19.3).
Figure 19.3: InterSLIP Setup window, shrunk.
If you have only one configuration, the only reason to leave the window expanded is if you need to edit your configuration frequently (which shouldn't be the case). InterSLIP Setup also remembers where on the screen you put it, so it's easy to put it out of the way and leave it active most of the time. InterSLIP Setup takes only 128K of RAM, so it's no great liability.
Note: There's a bug in InterSLIP Setup related to the way it remembers where you place the window. If you put InterSLIP Setup's window on a second monitor (assuming you have two attached to your Macintosh, as I do), then move or remove that monitor, InterSLIP Setup will almost certainly crash on launch. To solve the problem, throw away the InterSLIP Preferences file in your InterSLIP Folder. All that's stored there is the window location and the selected configuration file, so it's no loss.
You have two ways to use InterSLIP to connect to your host, manually and automatically. The manual method takes more effort because you must click on the Connect button in InterSLIP Setup, but it works much more reliably. The automatic method is exactly that, automatic, so whenever you launch Fetch or Eudora or any program that requests MacTCP services, InterSLIP kicks in and connects to your host. Or at least that's the idea.
The problem with the automatic technique is that it doesn't work all the time. When it doesn't work, you must usually force quit (hold down the Command and Option keys and press Escape) the MacTCP application that couldn't connect and then restart the machine, because something at a low level has been hosed. I had trouble using the automatic connection with a number of the applications I discuss later in this section, and everything based on HyperCard caused trouble. Even such usually well-behaved applications as Fetch sometimes caused problems, perhaps because the connection takes longer than it was prepared to wait. As neat and useful as the automatic connection feature is, therefore, I cannot recommend using it if you use a wide variety of MacTCP software. If you primarily use Eudora, you're probably okay -- but even then, make sure you have work in other applications saved before you attempt to start an automatic connection.
Either way, manual or automatic, when asked, InterSLIP dials your host, signs in, and then lets you get on with your work. You see various messages (they're stored in the dialing script and the gateway script) in the status area in the upper right of the InterSLIP Setup window that tell you what InterSLIP thinks is happening, most notably the Connected message when you have connected successfully. When you aren't connected, it should say Idle. As soon as you connect, the Connect button becomes disabled and the Disconnect button becomes enabled. There is no automatic disconnection, so you must make sure to click on the Disconnect button when you're finished.
Note: Many people have asked for a way to have InterSLIP disconnect automatically when they're finished, say, downloading their mail with Eudora; but there's no way this can happen without additional work on your part. Eudora has no way of knowing how the connection has been established or even that you use InterSLIP. And, InterSLIP can't know when you're done and when you might want to do something else. You could, however, script this behavior with QuicKeys, AppleScript, or Frontier. Using the latter two may be easier with InterSLIP/AE, a little program written by Leonard Rosenthol to control InterSLIP via Apple events. See the capsule review following this section.
Now you know all there is to using InterSLIP, but there are a few tricks that I want to mention.
I don't know how common this situation is, but with some SLIP hosts, for which you pay for the time you're connected, a timeout is set to hang up the phone line after a certain amount of idle time. If you think about it, this is a feature, not a bug; otherwise, you could get called away from the computer while using your SLIP account, forget about it entirely, and find yourself faced with a much larger usage bill. The timeout generally works well, but it does modify how you work.
If (and only if!) you use the same IP address every time you connect and your connection hangs up on you before you are finished, switch back to InterSLIP Setup, click on the Disconnect button, and then click on the Connect button. After you reestablish the connection, you can switch back into your MacTCP application and continue where you left off.
If, however, you use server addressing (in which the server assigns an IP address to you each time you log in), you must quit the active MacTCP programs before you reconnect via SLIP! Because you may end up with a different IP address when you call back after being disconnected, MacTCP programs may become extremely flustered at the change, and there's no predicting what could happen (but it probably involves crashing).
You must decide whether the timeout bothers you or not. As long as you can easily see the connection lights on your modem (assuming you're not using an internal PowerBook modem), you can tell when the line has hung up. If you want to keep the line open, you must keep doing things that access the network. One trick is to run Peter Lewis's shareware Talk program whenever you're connected, because it queries the network periodically. There are other tricks that work equally as well, such as having Eudora check your mail every four or five minutes.
More likely, though, you must figure out the proper methods of working. For instance, in a newsreader you can certainly open a bunch of articles or threads at once and then read them all on-screen. Unless you're a very fast reader, though, the connection will almost certainly get bored and hang up on you. Unless you want to treat the newsreader as an offline newsreader in this way, it might work better to read only one article or thread at a time, making sure that the newsreader periodically has to ask for more articles. In addition, you see that if you ask for a bunch of threads all at once, it takes a long time to get them, whereas if you go for the one-at-a-time approach, you can read constantly. Either approach has pros and cons, and it's up to you to decide which best fits your working style.
The program that can work best in this environment, of course, is one like Eudora or NewsHopper, which can log in, send and receive queued messages, and then log out immediately, letting you do all your work while disconnected from the network. Unfortunately, none of the freeware newsreaders have this feature quite yet, although it does exist in NewsHopper and the newsreader built into Synergy's VersaTerm-Link.
Frankly, I know little about using InterSLIP with System 6, mostly because I haven't used System 6 in almost four years. However, despite the note on the cover about requiring System 7, you may be able to use System 6 for some tasks.
To establish a connection with InterSLIP, you must have InterSLIP Control (a control panel) installed. As long as you have InterSLIP Control installed, InterSLIP should work the same as it does under System 7.
Note: Much of the Internet software released today requires System 7, so you may not be able to use it at all under System 6. That's the price of not upgrading. Eudora 1.4 and later require System 7, for instance, but Qualcomm keeps Eudora version 1.3.1 around for System 6 users. It's at:
ftp://ftp.qualcomm.com/quest/mac/eudora/1.3/eudora131.hqx
InterSLIP's primary neat feature, other than the fact that it works well, is its automatic connect feature, which unfortunately I find to be problematic. A feature I'd like to see in InterSLIP is the capability to show a terminal window of the connection (or even let you navigate in manually!) and capture a log of what happens during connection to ease troubleshooting.
One existing feature that I didn't much think of originally but have come to appreciate is that InterSLIP dials (and redials, if you have a dialing script that redials) in the background. That means you can click on the Connect button in InterSLIP and then go back to whatever you were doing until it finishes connecting. In contrast, MacPPP puts up a modal dialog that prevents you from doing anything else while it dials.
Even if InterSLIP doesn't have every imaginable feature, it's free and it's on the ISKM disk, so it's hard to complain too loudly. And, if for some reason you don't like InterSLIP or you have trouble getting it to work, you can always buy one of the other two SLIP programs or use PPP and MacPPP.
As I've said, InterSLIP is free from InterCon Systems. InterCon does not support InterSLIP, so if you have trouble, try posting in comp.sys.mac.comm. Doing so often results in help from other users or from InterSLIP's author. Also consider asking on a mailing list like the Apple Internet Users mailing list (send a message containing the command info apple-internet-users to listproc@abs.apple.com for information on how to subscribe). InterCon runs its own FTP site at ftp.intercon.com, and you can find the latest version of InterSLIP there or on ftp.tidbits.com:
ftp://ftp.tidbits.com/pub/tidbits/tisk/tcp/
ftp://ftp.intercon.com/intercon/sales/InterSLIP/
There are a few utilities that enhance the experience of working with InterSLIP, mostly making the act of connecting and disconnecting easier. Some other utilities help you time how long you spend online, which is useful for folks who call long distance or who must pay by the minute for their Internet connections. Unless I mention otherwise, all the utilities following are in:
ftp://ftp.tidbits.com/pub/tidbits/tisk/tcp/
Leonard Rosenthol's free InterSLIP/AE is a tiny application that does little more than enable you to control InterSLIP using scripts written in AppleScript, Frontier, or QuicKeys. It does have a minimal interface that lets you connect and can display the connection status and configuration. It's a must for anyone who wants to automate connections via InterSLIP and a scripting application.
ftp://ftp.tidbits.com/pub/tidbits/tisk/tcp/
Troy Gaul's freeware InterSLIP Strip Module brings control of InterSLIP to users of Apple's Control Strip on PowerBooks and to those who use Desktop Strip or DragStrip (like me) on desktop Macs. When properly installed, InterSLIP Strip Module enables you to connect and disconnect InterSLIP sessions, see the status of the InterSLIP session (I got an error in my screen shot -- oh well), and open the InterSLIP Setup application. If you use InterSLIP and Control Strip or one of the other utilities that supports Control Strip modules, this one's definitely worth a look.
ftp://ftp.tidbits.com/pub/tidbits/tisk/tcp/
InterSLIP Timer from Eric Preston is a small $5 shareware application that times both the session connection time and the cumulative connection time, making it easy for you to determine how large your Internet or phone bill will be at the end of the month. You must launch it manually, but you can also use it to start and end your InterSLIP session. Once active, InterSLIP Timer displays a small floating window that contains both the session time and the cumulative time.
Although I recommend InterSLIP as the first SLIP program you should try, that's mostly because it's free and it works well for many people. There are also several other implementations of SLIP that work better for some users. One of them, VersaTerm SLIP, is notable because it's easier to configure than either InterSLIP or the other commercial contender, MacSLIP.
The current version of InterSLIP is 1.0.1, and for most people, that's the version to stick with. However, Amanda Walker has tweaked some of the code in InterSLIP and produced a 1.0.2d2 (d2 means the second development release) version. It fixes some problems and introduces others (that's why it's a development release and not official). The main fixes include some MacTCP performance enhancements, the addition of the term "CSLIP" to the RFC 1144 TCP Header Compression checkbox, the ability to disable automatic connections, better detection of dropped connections, and most notably, support for 115,200 and 230,400 bps port speeds, mostly for compatibility with ISDN connections. If you're having trouble with InterSLIP and think 1.0.2d2 might help, give it a try, but again, don't complain if it doesn't help. The fact that InterCon makes it available at all (and it may have removed this version by the time you read this) is a huge help and must not be abused.
ftp://ftp.intercon.com//intercon/test/InterSLIP-1.0.2d2.sea.hqx
MacSLIP was written by Rick Watson of Hyde Park Software and is marketed and supported by TriSoft. MacSLIP 2.0 costs $49.95 and may offer the largest feature set of all three SLIPs. MacSLIP 2.0 has only a control panel and a MacSLIP extension. MacSLIP 2.0 sports an automatic connection feature, ships with a number of modem initialization strings, can notify you of your connection time, and displays statistics about the IP address, connect time, and serial line from within the control panel. My main complaint about MacSLIP is that the scripting language used to connect to your host -- although certainly full-featured -- is not the sort of thing a novice wants to mess with. Conversely, for an accomplished scripter, MacSLIP's scripting language may be just what you've always wanted. You can get more information about MacSLIP by sending email to info@hydepark.com, and MacSLIP 2.0 ships with MicroPhone Pro, or you can order it alone for $49.95 from TriSoft at 800-531-5170, 512-472-0744, or 512-473-2122 (fax).
Synergy Software claims that VersaTerm SLIP was the first commercially available SLIP for the Macintosh, and in my experience, it's also stable and reliable. VersaTerm SLIP includes an extension, a control panel, and an application, VersaTerm AdminSLIP, with which you interact. Of all the SLIP implementations, VersaTerm AdminSLIP uses the easiest method of writing a script, providing a simple dialog box for creating the login script. In addition, VersaTerm AdminSLIP includes a simple but useful terminal emulator. You can't buy VersaTerm SLIP by itself; it comes with Synergy Software's other VersaTerm packages, which range widely in price and capability. You also get the VersaTerm-Link program with VersaTerm SLIP; it's discussed in chapter 28, "Integrated Programs." You can contact Synergy to find out more about buying any of its programs via the Internet at maxwell@sales.synergy.com, via phone at 215-779-0522, or via fax at 215-370-0548.
Well, you should now be as much of an expert on SLIP, and InterSLIP in particular, as I can make you. The silly part of this and the previous two chapters is that once you have installed and configured MacTCP and either InterSLIP or MacPPP, your only interaction with them is opening and closing the connection. However, that assumes everything goes as planned, and as we all know, Murphy's Law has yet to be declared unconstitutional. Shall we move on to some troubleshooting information, then? Of course, if everything is working properly with your connection, in defiance of Murphy and the laws of nature, feel free to ignore the next chapter entirely.