Slip Networking

I followed the instructions in the June 1998 issue of Linux Journal. Thanks to Loris Renggli.

This is a network connection through the serial port. Once the SLIP is up and running, you will be able to use telnet, ftp, rcp, or lynx.

requirements:

two computers - root access on both

free serial ports on both machines

 tcp/ip utilities:
 route
 ifconfig
 ping
 etc/services
 etc/hosts
 etc/protocols
 general utilities
 /bin/telnet
 /bin/sh
 slip compiled into the Linux kernel, or
 slip functionality thru modules- modprobe, slip.o

special serial cable or connector - "null modem"

 If you want to make one, here's how to do it:
 You need two connectors, which fit into your serial ports.  They can be either 9 pins or 25 bins. The important pins are:
 25 pin connector:
  pin 2 - write data
  pin 3 - read data
  pin 7 - ground

 9 pin connector:
  pin 2 - read data
  pin 3 - write data
  pin 5 - ground

To make a cable, all you have to do is connect the pins like this:

 ground <-> ground
 read data <-> write data
 write data <-> read data

My case:

1. 586 - 90 mhz - 32 meg running Debian Linux 2.1 -standalone - kernel 2.0.29

2. 586sx 233 mhz - 64 meg running Debian Linux 2.1 - standalone - kernel 2.4.5

My steps:

1. setup etc files on both computers

 protocols
 services

hosts - on 586 233mhz computer (superlinux)

127.0.0.1 localhost

 192.168.93.1 superlinux superlinux
 192.168.93.2 palmax

hosts - on 586 90hmz computer (palmax)

192.168.93.2 locahost

 192.168.93.2 palmax palmax
 192.168.93.1 superlinux

2. setup slip startup script files

slip-up.sh on machine 1 and

 slip-up.sh on machine 2 (see bottom of document for examples)

3. setup cable between the two computer

both my machines have two serial ports

 port # 0 is 0x3F8 irq 4 on both
 port # 1 is begin used for slip on both
 restart both machines

4. run slip-up.sh on both machines

5. test network settings and connection

route should print out localhost and other machine

 ifconfig should printout lo and sl0 address

then using ping should get response from remote computer for example: ping sag ping baby

6. have daemons running or available on each machine

inetd

 in.telnetd
 in.ftpd

7. enjoy it!

telnet should log in to remote

 ftp can be used to transfer files

8. setup NFS for mouting network drives

slip-up.sh on machine 2 - superlinux:

1. !/bin/sh

 slattach -s 115200 -p slip /dev/ttyS1 &

  /sbin/ifconfig lo up
  /sbin/route add 192.168.93.1 
 /sbin/ifconfig sl0 192.168.93.1 pointopoint 192.168.93.2 up
 /sbin/route add 192.168.93.2 dev sl0

slip-up.sh on machine 1 - palmax:

1. !/bin/sh

 slattach -s 115200 -p slip /dev/ttyS1 &

  /sbin/ifconfig lo up
 /sbin/route add 192.168.93.2 
 /sbin/ifconfig sl0 192.168.93.2 pointopoint 192.168.93.1 up
 /sbin/route add 192.168.93.1 dev sl0

NOTES:

Setup /etc/networks to get the computer names to work as replacement for the ip numbers

Old Slip Networking

revision history:

  rev 4 - 2001 July 15 redid - saved old as link
  rev 3 - 2001 june 24 transfered to wikiwiki
  rev 2 - 1999-8-22 corrected some typos
  rev 1 - 1999-8-19 first draft - based on plip document

Old Slip Networking