SUMMARY: help with slip (repost)

From: David N. Blank-Edelman (
Date: Fri Aug 28 1992 - 05:37:53 CDT

  A while back I asked about SLIP between a Mac and a Sun. Shortly
after I sent the mail, I saw a news article addressing this issue
which helped me get connected. I noted the article in my SUMMARY on
the subject, but was rightfully dunned by several people for not
including its text in my SUMMARY (I didn't want to distribute it
without the author's permission). Once I got his permission, I
attempted to mail a revised SUMMARY but it doesn't appear this
actually got through (based on the requests for the article I've seen
since). So, for posterity, here it is:

>From Sat May 30 22:42:00 1992
Newsgroups: comp.sys.mac.comm
From: (Don Gilbert)
Subject: How to configure a Sun as a SLIP server
Organization: Biology, Indiana University - Bloomington
Date: Sat, 30 May 92 18:39:22 GMT

This document is directed at Unix workstation administrators/programmers who may want to set up a SLIP service for Mac/PC/Unix dialup users.

SLIP is Serial Line IP. A SLIP server enables a home computer (Mac, PC, or Unix) to connect thru telephone dialup to the Internet. For Macintoshes, there are now 2 or 3 vendors selling a SLIP module to work with Apple's MacTCP software. There are also other, and probably better, ways to get a SLIP service than is described here. Some terminal server hardware includes SLIP support. Some commercial venders sell dialup IP service.

This describes my results recently from two days of hassles w/ free slipware for Sun Sparcstation (sun4c model using SunOS 4.1.1). Your mileage will vary depending on the Unix workstation you wish to set up as SLIP server. The Mac side is much easier.

Suppose your organization's class B network number is 139.123, and you are subnetting with a class C-sized network mask of 0xffffff00. Your departmental LAN is subnet, with an ethernetted Unix workstation called SunGod ( among the other workstations on this subnet. A modem is attached to one of SunGod's serial ports. A Macintosh named MacHome wishes to connect to the network thru SLIP.

Steps for this, using freely available slip software for Suns are:

1) plug a modem into a serial port on your Sun.

2) build in the SLIP pseudodevice into the Sun Unix kernel. Use either slipware 4.0, cslip (compressed slip) based on 4.0 or slipware 4.1 [see ftp refs below]. Unix kernel setup is only for knowledgeable Unix programmers/administrators.

3) compile and install the SLIP driver program(s). This may be "sliplogin", which also uses the /etc/hosts.slip table and which seems most convenient for multiple users, and which leaves your Sun serial port available for regular dialins at other times. Or "slattach" which attaches a serial port on the Sun as a semi-permanent SLIP port. 4) Assign MacHome an IP address, for example, in Sungod's /etc/hosts table:

If using sliplogin, construct /etc/hosts.slip table: # /etc/hosts.slip # notes: local-address is the SLIP server (SunGod) # remote-address is the dialup computer (MacHome) #username mode local-address remote-address netmask myaccount normal

5) Link the remote IP host MacHome to SunGod's ethernet address. This rather important step is not discussed in the slipware documents. Use command like "arp -s RemoteIPaddress LocalEthernetAddress pub". See arp manpage. Interactively as root on Sungod for testing and/or in Sungod's /etc/rc.local add this line: arp -s machome `ifconfig le0 | sed -n "/ether/s/ether//gp"` pub 6) On MacHome, if for instance Versaterm SLIP driver is used with MacTCP, configure Versaterm AdminSlip properly. If using cslip on Sungod, must check the compressed slip option on Mac, otherwise uncheck this. Insert the IP address of MacHome, the net mask (as above) for your subnet setup, and a gateway IP number, as used for other computers on this subnet.

7) dial up from MacHome to SunGod's modem using your Mac Slip program (e.g., Versaterm AdminSLIP). Log in w/ user and password as if you were logging on for interactive session. If using sliplogin, you can run this kind of script at logon (where modem is connected to SunGod's /dev/ttya serial port): #!/bin/sh /usr/bin/mesg n # may not be needed stty -tostop # may not be needed # sliplogin, called by user, reads /etc/hosts.slip for local:remote nodes exec sliplogin < /dev/ttya

8) Slip should now be working, try running NCSA Telnet (MacTCP), GopherApp, Eudora (MacTCP) and other such MacTCP programs. 9) When session is done, hang up slip line. Modem on SunGod now should be free for other users' regular or slip sessions. Repeat steps (7) to (9) as needed. Don't call me in the morning.

References: All needed slip server software for Sun Sparcstation and probably other Unix computers, see 102751 Aug 22 1991 csn-slip-package.tar.Z < contains slip-4.1 26148 Oct 31 1989 slip-4.0.tar.Z < useable, see also cslip version

and 271573 Apr 3 1990 cslipbeta.tar.Z < usable, slip-4.1 may be better

The Morningstar manual for their PPP/SLIP software is available freely for ftp at It contains information I needed to set up a slip server that I could not find in any of the free SLIP packages. See and /pub/ppp/Free-SLIP-and-PPP >From Steve Dorner's recent SLIP for Mac review:

VersaTerm SLIP comes with VersaTerm 4.6.2, which goes for about $90 mail-order, and includes an FTP server and client, MacTCP, a Telnet connection tool, and a time server and client. Educational institutions are eligible for a reduced price arrangement. Contact Synergy Software, ads in many Mac magazines or via mail order software houses.

MacSLIP is $49.95. Site licenses will be available for a reasonable price. Contact for more information.

InterCon has announced a Mac SLIP module. Contact Help@Intercon.Com

-- Don Gilbert biocomputing office, biology dept., indiana univ., bloomington, in 47405

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