Using SLiRP with OS/2 Warp


Making the PPP Connection with the Dialer

This little tutorial will teach you how to setup OS/2 Warp to connect to SLiRP in PPP mode. Before you go on: The instructions below are certainly not a complete installation manual. See the references above for that, I couldn't have done it better. Instead, the little details of the interaction between SLiRP and the IAK are the main focus here. I'm using my own settings as an example. PPP was chosen because it's easer to configure and more robust on "non-transparent" lines (e.g. if you, like me, dial in through a terminal server which eats up certain characters).

(You might want to setup a SLIP connection without using the Dialer. If you prefer the command line or you just want to login manually because it's easy to make mistakes in login scripts, read this).

Here's how to setup Warp's IAK to use SLiRP on the host.

  1. Start the Dialer.
  2. Select Add Entry. You will see a window such as the following:

  3.  

     

  4. Set Name, Description, Login ID, Password, Phone Numer and Connection type as desired. Again, see above if you need help on this.
  5. Fill in your Login Script. Mine looks like this:
  6. \r
    sara-ts2
    telnet\scarol.wins.uva.nl
    ogin:
    [LOGINID]
    assword:
    [PASSWORD]
    carol
    slirp\s-b\s14400\s-P\s""mtu\s552""\s""mru\s552""\s""asyncmap\sFFFFFFFF\s""\s""escape\s0,11,13,1D,FF""
    The first line is what you send, the second line respresents the string to be waited for, you send the third line etc. As you can see, I dial in through a terminal server named sara-ts2. From the Annex prompt, I telnet to my host (telnet is more transparent than rlogin). Then I wait for the login and password prompts. I use ogin and assword in my scripts so it doesn't actually matter if the first letter is a capital or not.

    Then I wait until I get my Unix command line prompt. This is a little bit tricky. Most of the prompts end with > . The Dialer seemed to have difficulties with this character (and with % for example). That's no surprise, since the whole Login Sequence is passed "as is" through the command line interpreter to the PPP.EXE program. And the > character is reserved for redirection. Perhaps it's possible to "escape" this character, but I didn't want to find out. Instead I just wait for the string carol (my host) since I use the TCSH shell which allows me to put the hostname in the prompt as well. SLiRP's PPP implementation requires its arguments to be placed between double quotes. Again, these quotes are not handled all that well on the OS/2 command line but you can "escape" them by doubling each double quote. Spaces must be converted to \s. As you can see, all this doesn't make the script very readable. Here follows the same SLiRP startup command but this time in a format you would use by typing from the command line (I assume you have SLiRP in your path):

    slirp -b 14400 -P "mtu 552" "mru 552" "asyncmap FFFFFFFF" "escape 0,11,13,1D,FF"
    These "worst case" settings were suggested in README.PPP of the SLiRP documentation. They should enable you to get started. By the way, the MTU and MRU have to be the same with PPP, according to the NOTES included with SLiRP.

    Instead of a response script, you can also specify a REXX script in this window. Some people use PPPDial, since the Dialer itself doesn't support redial and multiple phone numbers.

  7. In the next page, use as Your IP Address 10.0.2.15. If you have changed SLiRP's default address, use that one.
  8. Fill in the Destination IP address, Netmask, MRU and VJ compression if these are required (indicated by an asterix). The PPP protocol seems to figure these out itself. If you use the SLIP protocol with a response script or (REXX) script it depends which fields are filled in by the script and which ones you need to fill in manually. A Netmask of 255.255.255.0, an MRU of 552 and VJ checked on are probably wise choices.
  9. In the Domain Name Server field, type the IP address of your DNS. If you don't know your DNS, ask your sysadmin, or just start SLiRP on your Unix host and watch for a line that says something like:

  10. IP address of your DNS(s): 146.50.1.20, 146.50.4.20, 146.50.2.20
    and pick one of those set of numbers to use.

  11. On the next page, choose your default servers. This is standard IAK configuration stuff.

  12.  

     

    On the last page, choose the COM port and the desired baud rate. I left the rest unchanged.

  13. Done - Now close this window. The Dialer will ask you to Save, Discard or Cancel. Click Save to return to the Dialer's main window.
With the Dialer setup done, you are ready to login and start using SLIP/PPP.
  1. Start the Dialer.
  2. Select the entry you've just set up and click "Dial".
  3. Now the modem should start to dial and after you get a CONNECT, your script should kick in. It's easy to make mistakes, so if your script doesn't work, look again carefully. Once you get the message "Connector completed" you've got a running PPP connection.
  4. You can start using TCP/IP applications. One of the first things you'll probably want to do is use "Retrieve Software Updates" for the latest WebExplorer etc.

Notes

Almost every application in the IAK worked right out of the box for me (after the usual amount of configuring of course). I couldn't get the WebExplorer working though. Or HTML pages rather, since I could do Gopher stuff with the WebExplorer. Also, I cannot do FTP uploads (or Zmodem uploads for that matter). I'm quite positive these two problems have to do with this terminal server I'm using (or my host) since other people have reported no problems with the WebExplorer.


Jacco de Leeuw