Using SLIP/PPP

Revised: September 18, 1998

Subscriber access includes free use of virtual SLIP and PPP services via the SLIRP program. You will need a SLIP or PPP driver program and software for each service you wish to use from your home computer, e.g. Web, Usenet News, Finger, IRC, etc. Ripco also offers dynamic and dedicated 'true SLIP/PPP' with your own IP address and hostname.

To log in with SLIP instead of the shell, put an uppercase 'S' in front of your login name at the start of the call. To log in with PPP, put an uppercase 'P'.

We have login scripts for many different drivers and operating systems. Software for SLIP is available in the 'download program' (just enter 'cd slip' at the download prompt), and via our web site.


Setting up your system for PPP access

Because SLIP is difficult to configure correctly, you should get a driver that is capable of making PPP connections. Your IP address under SLIRP will be 10.0.2.5, but you should be able to leave that and other fields blank and your PPP driver will fill them dynamically.

The only fields that are mandatory are the primary and secondary Domain Name servers.

E-Mail Information

Your e-mail address will still be >user<@ripco.com, you should set this as the reply address if your software has provisions for one.

Other common services

SERVICE		SERVER TO USE          PORT
Nameserver	209.100.227.1            42
News/NNTP	news.ripco.com          119
Popmail		pop.ripco.com           110
Mail/SMTP	mail.ripco.com		 25
WWW/HTTP	www.ripco.net            80 
Gopher		gopher.ripco.com         70
login		shell.ripco.com 	 23

Differences in using SLIRP

One common question is "What do I lose using SLIRP instead of SLIP?". Because you do not have a unique IP address, you will not be able to use your machine as a server, and you cannot run a local 'talk' or 'ping' program. IRC WILL WORK, however CTCP services will not be available.

For users who are unable to configure the virtual PPP (scripted login), or who need features that 'virtual' PPP does not support, we provide a true dynamic-IP PPP account, at a $5/month surcharge over the basic account rate.

Switching to dynamic-PPP instead of the usual 'virtual' PPP usually solves any problems with multiplayer games, as well as improving compatibility with the new chat, messaging, and videophone software.

Example Configurations

Here are some common blanks in SLIP and PPP setup software. IP: 192.0.2.1 <-- Should work for all users - See SLIRP FAQs Netmask: 255.255.255.0 <-- Default DNS (Nameserver): 209.100.227.1 Secondary DNS: 206.54.224.1 Domain suffix: ripco.com Time server: blank Packet vector: blank MTU: 1500 <-- Must be at least 1500 RWIN: 4096 <-- Default MSS: 1460 Slip-Enabled: 1 <-- On or Yes (1) Slip-Port: <-- Your Com port Baudrate: 19200 <-- 14400 may not work! Hardware Handshaking: 1 <-- Depends on the setup of your modem Compressed SLIP: 0 <-- Off or No - Very Important! slip-handshake = 1

Common SLIP/PPP drivers

Macintosh

The only commonly available driver for Macintosh computers is MacTCP, MacTCP will come with System 7.5. but until then you'll have to find it through other means (it's not available on the net), or purchase it from Apple.

One option is to get a copy of "Internet Starter Kit" by Adam Engst. It comes with a floppy containing MacTCP, InterSLIP, and some other useful stuff. InterSlip is also available via FTP from InterCon at ftp.intercon.com

You'll also need a copy of NCSA Telnet, available on zaphod.ncsa.uiuc.edu in Mac/Telnet/Telnet2.6/Telnet2.6.sit.hqx. Telnet is a good TCP/IP program to use to test whether your connection has worked.

Install InterSLIP by running the installer you've downloaded, reboot, then go into the "InterSLIP Setup" program. Select "New" from the File menu, enter any name for your new config, then double-click on the name when it appears in the main window. In the ensuing modal dialog, you'll probably only need to set a few things:

  1. Your baud rate. For a 14.4kbaud modem, try setting this to 19200 (it worked for me); if that doesn't work you can always try 9600 later.
  2. An IP address. You can enter anything here, since SLIRP doesn't set up an individual IP address for you. This field usually gets ignored. I set it to 1.1.1.1; if that gives you trouble since some apps try to use it directly, then set it to 192.0.2.1 which is officially defined to be "nothing".
  3. The numeric IP address of one of your name servers (prefreably your "primary" name server), 209.100.227.1
  4. The "MTU Size". SLIRP documentation recommends setting this to 1500.

    Leave the "Dial Script" and "Gateway" set to "Direct Connection".

    Now, install MacTCP, reboot, and open its control panel. Click on the InterSLIP icon that appears there, then click on "More".

    Click "OK", then reboot to apply thee changes.

    Now your Mac should be all set!

    You should now be able to type "slirp" from your Unix prompt and have it reply "Ready to start your SLIP software." Note that if you ever want to stop SLIRP and get back to a Unix prompt, just type Control-C slowly five times, such that more than two seconds go by between the first Control-C and the last one.

    Oh, and make sure that your terminal program isn't set to automatically hang up when you quit out of it; you will need to be able to quit out of your terminal program without killing your dial-in connection to your Unix host. Right now, quit out of your terminal program then run it again, and if you find yourself still going as if you had never quit, then you should be okay.

    Okay. Now for the moment of truth.

    At a Unix prompt, run "slirp". It should reply "Ready to start your SLIP software."

    Quit out of your terminal program, open "InterSLIP Setup", make sure the name of the configuration you created earlier is selected, and click the "Connect" button. If all goes well, then the word "Connected" should appear at the top of the window. Note that as long as this says "Connected", you will not be able to run your terminal program, since InterSLIP has grabbed the serial port. My copy of Zterm will hang if I try to run it while InterSLIP has the serial port.

    Now run NCSA Telnet. Try to open a connection to the Unix host you usually connect to. If it fails to connect, then try again, this time giving the numeric IP address of the Unix host; if it fails with the name but works with the number then this means that you haven't set your name servers correctly in the MacTCP control panel or in InterSLIP.

    If you've run into problems before this point (InterSLIP doesn't connect, or NCSA Telnet gives you errors), and you can't figure out what the problem is, then post on comp.sys.mac.comm to ask for help. Describe exactly what step of the installation you got up to before things started happening funny.

    On the other hand, if things work for you, then you're all set! Dicsonnect from InterSLIP and go back into your shell account to download a copy of Dartmouth's "FTP" program from a Mac ftp site, and try to use that to download a copy of NCSA Mosaic. Being able to finally run Mosaic on your Mac is a fitting reward for getting all of this to work successfully.

    You might also want to set up InterSLIP to dial in automatically for you. FTP to ftp.netcom.com, and get the file /pub/mealiffe/netcom/tia-interslip-script. Put it into the folder "System Folder:Preferences:InterSLIP Folder:Gateway Scripts" on your Mac. You might have to change its type/creator to CNFG/ISLP. It's a text file, so you can edit it if necessary. Make any necessary changes to your Unix .login file so that you will always automatically get to a Unix prompt when you log in. If your prompt does not end in a percent ('%') character, then use a text editor to edit the script you just downloaded to put the correct character there (it tells you where to make the change). I also had to add an extra zero to the number after every "matchread" statement in the script (for example, where it said "matchread 50" I made it "matchread 500") to prevent my connections from timing out so easily before they had finished connecting.

    Go back into the InterSLIP Setup application and edit your configuration: set the Dial Script to "Hayes Compatible" and enter the Unix dial-in phone number, and set the Gateway Script to the script you just downloaded and edited. If all went well, then whenever you try to run any TCP/IP application on your Mac when you're not already connected, InterSLIP will automatically dial in for you and establish the connection. Easy as that. :-)


    Other resources for more information: