Chip 1998 September/CHIP Eylül 1998.iso/Slackwar/docs/mini/PLIP

Text File | 1996-09-04 | 33KB | 882 lines

            LINUX PLIP MINI-HOWTO

Last Update: 22/07/1996 (dd/mm/yyyy date format)
Copyright: 1996 by Andrea Controzzi <[e-mail]>
       See the copyright message below.

This HOWTO will hopefully let you build and use a Parallel Line Interface
Protocol.

NOTE: this is the second release. There are many changes and lots of
enhancements, but there will be surely grammar and spelling errors
(english is not my native language) and, unlikely but possible, some
wrong or outdated info. PLEASE let me know about any errors to help me
provide the correct information for everybody.

For any question, error correction, comment and/or suggestion, my E-Mail
address is: [e-mail]. Feel free to mail me any time you
need help. Sometimes I won't answer immediately, but I'll answer. If it
happens that you don't receive anything from me after 2 weeks, this means
that our mail system has trouble: do not hesitate to mail me again, it's
my duty to help you.

First of all, a lot of technical information come from the net-2-HOWTO, by
Terry Dawson. This mini-HOWTO is not supposed to cover other aspects and/or
replace the net-2-HOWTO: my goal is to give you a way to install a PLIP
permanent connection quickly, *ONLY* this. All the other info come from
my personal experience and the help of many users that sent me comments
and information.

Read the net-2-HOWTO and the other docs for the general information about
the network and the config files I suggest to change.

The following is the index of the contents; you can quickly find the right
paragraph searching for the string __nn__ where nn is the paragraph number.

INDEX
=====

0) Introduction: what is PLIP and why should I use it?
1) Hardware required to use PLIP.
2) Reconfigure the kernel.
3) Setting up the configuration files.
4) Activate the PLIP link.
5) Kernel messages at boot time.
6) FAQ.
7) A quick PLIP installation.
8) Patches to make PLIP and LP live together.
9) A PLIP LINK BETWEEN DOS AND LINUX
10) Questions? Comments? Send me feedback.
11) Where to find new releases of this mini-howto.
12) Credits.
13) Copyright message.


__0__ INTRODUCTION: WHAT IS PLIP AND WHY SHOULD I USE IT?

There are many ways to create a connection between multiple hosts. PLIP,
like SLIP, allow a local connection between two machines via the parallel
ports.

A PLIP connection is very similar to the SLIP (with a leased cable) one,
but uses parallel ports instead of the serial ports. Parallel ports
transfer more than one bit at a time, this means it is possible to
achieve higher speeds than with a serial interface.

The PLIP interface is fast enough to allow some decent tcp/ip functions,
like NFS. So, you may have a computer with all your Linux stuff and
another with only the minimal system, where you can mount all the rest
from the main machine.

The disadvantage is that most users have only one parallel port, this
means that you won't be able to print and use PLIP together.  Until the
last kernels, even with two or more parallel ports, using PLIP and the
printer was impossible without using the kernel modules or other tricks.

This disvantage can be also eliminated, if you have two or more  parallel
ports, applying a patch. Please see below in the "Patches to make PLIP and
LP live together".

Finally I am now able to give a hopefully good way to set up a PLIP link
between DOS and Linux.

__1__ HARDWARE REQUIRED TO USE PLIP

The hardware required to set up a PLIP interface is (obviously) a free
parallel port in both the machines and the cable.

About the cable, this is what is written in the plip.c file, in the kernel
1.2.13 source:

  The cable used is a de facto standard parallel null cable -- sold as
  a "LapLink" cable by various places.  You'll need a 12-conductor cable to
  make one yourself.  The wiring is:
    SLCTIN      17 - 17
    GROUND      25 - 25
    D0->ERROR   2 - 15          15 - 2
    D1->SLCT    3 - 13          13 - 3
    D2->PAPOUT  4 - 12          12 - 4
    D3->ACK     5 - 10          10 - 5
    D4->BUSY    6 - 11          11 - 6
  Do not connect the other pins.  They are
    D5,D6,D7 are 7,8,9
    STROBE is 1, FEED is 14, INIT is 16
    extra grounds are 18,19,20,21,22,23,24

But I strongly advice you to read the /usr/src/linux/drivers/net/README1.PLIP
file for more info about the cable.

In my opinion you should avoid building your own parallel null cable. A
self-made cable may save very little money, but can add lots of headaches.
If you wish to build your parallel cable, remember that you're doing it at
your own risk, I reported exactly what is written in plip.c but I don't give
warranties.

A final word about cable length: long cables (i.e. more than 10 feet or
3 meters) may bring problems due to radio interference. If you need long
cables you should use good and well shielded cables, but very long cables
are not recommended: I think the maximal cable lenght should be 15 meters
(50 feet).

Anyway, someone mailed me that his/her 100 foot (30 meters) cable works
fine; if someone really wants to try a PLIP connection between the
office and his home (200 meters away), and has the money to spend, then
simply try it: in the worst case it just won't work!

__2__ RECONFIGURE THE KERNEL

You're supposed to already know how to configure and compile the kernel,
otherwise you must get some doc (kernel-howto or other guides). Thanks to
the cool work made by the kernel guys, recompiling the last kernels is a
really easy jobs also for "common" people, so just do it. Anyway, for the
sake of completeness, here is a quick summary of what you must do:

NOTE: I suppose you are using the 2.0.xx kernel series. Now there is
no need to keep the 1.2.xx kernels.

I will suppose that you use menuconfig to set up the kernel options, but
the other tools are equivalent. I'll show how to do it with menuconfig:

  #make menuconfig

I strongly advice to select

  Loadable module support  --->

and enable the

   [*] Enable loadable module support

and, if possible (i.e. you have modules.2.0.0) the

   [*] Kernel daemon support (e.g. autoload of modules)

Then go back and choose

  Networking options  --->

where you should choose at least

   [*] Network firewalls
   [*] TCP/IP networking
   [*] IP: forwarding/gatewaying

The go back and choose at least

   [*] Network device support
   <M> PLIP (parallel port) support

If you use modules I definitely advice you to set up PLIP as a module. If
you do so you can also, if you need to use a printer, go to

  Character devices  --->

and set up as a module the

<M> Parallel printer support

Now you have enabled the kernel support for PLIP. If it's the first time
that you compile the kernel look at all the other options then save and
exit.

Finally compile with

  #make dep ; make clean
  #make zlilo

And, if you use modules

  # make modules
  # make modules_install

__3__ SETTING UP THE CONFIGURATION FILES

First of all remember to backup all the files you will change,

  #cp rc.inet1 rc.inet1.BACKUP

may be a good idea.

Now, if you don't have it done already, you must choose the IP addresses
of the two machines. In my examples I'll use a couple of example IPs for
the IPs that you'll write, in the standard xxx.xxx.xxx.xxx format.

In the /etc/rc.d/inet1.rc file of both the machines add this (better if in
the last part of the file):

/sbin/route add -net ${NETWORK} netmask ${NETMASK}

Where NETWORK and NETMASK should be set up previously. If you don't know how
to do it, please read the NET-2-HOWTO.

You may safely ignore these variables only in the following case:

If you only want to connect two machines on a standalone network, you may
pick-up any IP address, say 200.0.0.1 and 200.0.0.2 respectively.
In this case you can safely put NETWORK="200.0.0.0" and NETMASK="255.255.255
.0". These are the example IPs that I use in my Quick PLIP Installation (see
below).


NOTE: 200.0.0.1 and 2 are only example IPs, I advice not to use these
numbers definitively because they could be the addresses of real
hosts on Internet!

I strongly advice to choose your address between the "private address"
intervals:

      10.0.0.0        -   10.255.255.255
          172.16.0.0      -   172.31.255.255
          192.168.0.0     -   192.168.255.255

In the file /etc/hosts of both the machines you should add the entries with
the IP of the machines that you connect via PLIP. In my example, the entries
are:

200.0.0.1       one             # this is the "one" IP address
200.0.0.2       two             # this is the "two" IP address

Where one and two are the names you have chosen for the two hosts.

If you want to activate the NFS, beside answering yes during the kernel
configuration, you must add in /etc/exports the entries that describe the
directories that you wish to export. In my example, to be able to mount
the directory /usr, you should add this entry:

 /usr                          two (ro)


__4__ ACTIVATE THE PLIP LINK

  Finally, these are the commands, that must be executed with root rights,
that activate the PLIP interface (of course the cable must be already plugged
correctly).

First of all confirm that there is no lp device present:

  #cat /proc/devices

You mustn't see any reference to lp like this:

 6 lp

Again I use the name one and two, as example. On "one" you must type:

  #ifconfig plip1 one pointopoint two up

Check that it worked...

  #ifconfig



 .....
 .....
 plip1     Link encap:10Mbps Ethernet  HWaddr FC:FC:C8:00:00:01
           inet addr:200.0.0.1  P-t-P:200.0.0.2  Mask:255.255.255.0
           UP POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0
           TX packets:0 errors:0 dropped:0 overruns:0
           Interrupt:7 Base address:0x378

NOTE: if you use modules without the kerneld daemon (that autoloads the
proper modules on demand) remember to

  #insmod plip

before the ifconfig. If you are paranoic check that the module has been
loaded with:

  #lsmod

Module:        #pages:  Used by:
plip               3            0

Add the route to two...

  #route add two

And, if you want also the NFS for two:

  #rpc.portmap
  #rpc.mountd
  #rpc.nfsd

On "two" the commands are the same, but you must write one instead of two
and vice versa.

One of your machines is likely to have only the PLIP connection, if this is
true, you may also type:

  #route add default gw one

on that machine. In my example above, two is a laptop with only a PLIP
connection with one, so I type the above line on two.

Finally check with a

  #ping two

from one and a

  #ping one

from two to see that all is working.

Of course you may want to have all these commands automatically done by a
script or at boot time. You must only create a script that execute these
commands: now you may invoke it as root when you need, or you may add a
command (in /etc/rc.d/rc.inet2) that calls it at boot time. If you want to
use my Quick PLIP Installation, you will find all the config files and the
script. NOTE: this file may be outdated...sorry.

__5__ KERNEL MESSAGES AT BOOT TIME

After you've reconfigured and compiled the kernel with PLIP support enabled,
examine the messages with the dmesg (8) command.

You should get something like this:

NET3 PLIP version 2.0 [e-mail]
plip1: Parallel port at 0x378, using assigned IRQ 7.

Of course if you're using modules you'll see this message when you (or
the kerneld daemon) insmods the plip.o module. Depending upon your
klogd and syslogd configuration the plip message could have been stored
in your system log files: don't panic if you don't see the above message.
If lsmod shows that the plip module is loaded, then it's enough.

__6__ FAQ

This section will (hopefully) solve your problems. If you have any other
question, feel free to mail me anytime.

The question is listed with a =, the answer(s) with a -

= I get these messages at boot time:
    SIOCSIFADDR: No such device
    SIOCADDRT: Network is unreachable
  and when I try to set up the link as written above, I get again error
  messages like:
    SIOCSIFADDR: No such device
    SIOCSIFDSTADDR: No such device
    SIOCADDRT: Network is unreachable
    mount clntudp_create: RPC: Port Mapper failure - RPC: Unable to send
- The kernel, for some reason, hasn't PLIP support enabled. This could be
  due to:
   . You didn't answer yes to "PLIP support? " during kernel configuration.
   . You answered yes to "Printer support? " during kernel configuration.
   . You compiled PLIP as a module, so you must load it.

= Is there a way to support both PLIP and LP, beside modules, perhaps with
  two parallel ports?
- Yes, so far there are two ways, described in the "Patches to make PLIP
  and LP live together":
  . You can apply a patch to make the kernel support both.
  . You can apply another patch to make the kernel use a parallel port
    for PLIP and another for LP.

= I have created the script that connects my 2 computers. I set up the
  link automatically in my rc.inet2, where I call a script that creates
  the link and enables VFS.
  My "two" hosts mounts some "one"'s directories; I have added the
  correct entries in "two"'s /etc/fstab.
  If I boot "two" when "one" is down, "two" halts for some minutes
  on the "mounting remote file systems...".
- This happens because "two" waits to mount the "one" filesystems, but
  if "one" is down you must wait until "two" is bored of waiting.
  To avoid this, you may:
   . Comment out in rc.inet2 the command that mounts the remote filesystems
   . Remove the entry in "two"'s /etc/fstab and mount the remote filesystems
     manually when and if you need.

= My link is up, but ping fails. I receive the following message from the
  kernel:       plip1: timed out (1, 89)
- This means that the "your side of the link" is working, your machine
  sends the signal, but the "other side" isn't answering for the following
  reasons:
  . The cable isn't plugged properly or is broken or is wrong.
  . The "other side" machine has not PLIP up.
  . You are linked with a notebook with a not proper parallel port, see
    next question.

= I have installed the PLIP connection but if I ping I get 100% data loss.
  I connected my desktop with a notebook.
- Some notebook's parallel ports aren't good for PLIP, because they are
  only "printer ports", i.e. they can only transmit but not receive the
  data. So far I don't know if there is a way to make them work.
  The only hope is:
  . Look at your notebook setup, perhaps there is a way to configure
    the parallel port as a parallel port instead of a printer port.
  . Try plip mode 0. Alas I don't know how to do it and/or if it works
    or is still available in the last kernels.

= What speeds can I achieve with PLIP?
- This is an hard question to answer to, because there are MANY factors
  that can change deeply your performance:
  . The CPU speed on both the sides of the link.
  . The parallel port type and settings.
  . The system load.
  . What do you use PLIP for.
  Just to give a rough idea, you should achieve about 40Kbytes/sec, much
  faster than any serial rate and near to a low-level ethernet card.

= What happens if I need to ifconfig up and ifconfig down many times plip1?
- Seems that you need to add a -arp to the ifconfig command, except for
  the first time after each boot. I don't need, but perhaps someone does.

= I have read the IP numbers reserved for private networks and your 200.0.0.1
  and 200.0.0.2 are not in these ranges. Shouldn't they be changed?
- Yes, they should. But as I underline since the beginning I choose these
  IP addresses only because of their simplicity, you are free to change
  them as you wish. Here is a cut from the net-2-howto:

    RFC1597 has specifically reserved some IP addresses for private
    networks.  You should use these as they prevent anything nasty
    happening if you accidentally get connected to the Internet. The
    addresses reserved are:

      10.0.0.0        -   10.255.255.255
      172.16.0.0      -   172.31.255.255
      192.168.0.0     -   192.168.255.255

= Is there a way to fine tune PLIP parameters without editing the source
  code?
- Yes, there is! Try the /sbin/plipconfig command. See the man page for more
  info.

= I'm running Debian GNU/Linux, and under Debian, the files /etc/rc.d/rc.inet1
  and 2 do not exist. Where must I write the plip configuration commands?
- In Debian GNU/Linux you must edit /etc/init.d/network, where you have to
  put all the commands that should stay in rc.inet1 and 2.

= I have some problems linking two hosts with PLIP. The first has the latest
  kernel, the second still uses the 1.0.x PLIP version: is this a problem?
- Yes, it's much better, where is possible, to have the same PLIP version on
  both ends.

= PLIP support in some 1.3.x kernel doesn't work. What happens?
- Remember that 1.oddnumber.x kernels are under development: the "gods"
  that work hard every day to make linux better than the day before
  sometimes fail to give us "mortals" stable kernels. Right now a kernel
  2.0.xx release should be stable.

__7__ A QUICK PLIP INSTALLATION

Before doing this mini-HOWTO, I created a quick PLIP installation set of
files. In few minutes, beside compiling the kernel, you should be able to
set up a PLIP interface. The tarred and gzipped set of files may be found
on my Home Page, at

http://www.cli.di.unipi.it/~controzz/intro.html

Perhaps someone will let my files available at some ftp site.

__8__ PATCHES TO MAKE PLIP AND LP LIVE TOGETHER

The best way to make PLIP and LP live together is to use kernel modules: you
can load plip.o and unload it when you need to print or vice versa.
If you do really need to use both PLIP and LP, try the following patches.

  _8.1_ PLIP AND LP TOGETHER ON THE SAME PORT
If for some reason you wish PLIP and LP supported directly by the kernel,
you can try these patches.

You must modify the following pieces of code, but *backup* the files
before:

--- begin ---

******** modifications to linux/drivers/char/lp.c ***********************
struct lp_struct lp_table[] = {
        { 0x3bc, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL,
NULL, },
/*      { 0x378, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL,
NULL, },
        { 0x278, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL,
NULL, },
*/
};
#define LP_NO 1

******** modifications to linux/drivers/net/Space.c ********************
#if defined(PLIP) || defined(CONFIG_PLIP)
    extern int plip_init(struct device *);
    static struct device plip2_dev = {
        "plip2", 0, 0, 0, 0, 0x278, 2, 0, 0, 0, NEXT_DEV, plip_init, };
    static struct device plip1_dev = {
        "plip1", 0, 0, 0, 0, 0x378, 7, 0, 0, 0, &plip2_dev, plip_init, };
/*    static struct device plip0_dev = {
        "plip0", 0, 0, 0, 0, 0x3BC, 5, 0, 0, 0, &plip1_dev, plip_init, };
*/
#   undef NEXT_DEV
#   define NEXT_DEV     (&plip1_dev)
#endif  /* PLIP */

---end---

Of course there is the standard disclaimer: I received these patches and
I put them "as I got them". This means that you try them at your own risk.
Anyway, your biggest trouble should be only restore the original files and
recompile.

  _8.2_ PLIP AND LP ON DIFFERENT PORTS
If you have at least 2 parallel ports you can try these patches, that
should allow you to use PLIP on a port and LP on the other.

--- begin ---

1. Comment out one line in kernel source file, drivers/char/lp.c.

struct lp_struct lp_table[] = {
{ 0x3bc, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL, NULL, },
{ 0x378, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL, NULL, },
/* { 0x278, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL, NULL, }, */
};
    3 -> 2

2. Kernel configuration

    PLIP (parallel port) support (CONFIG_PLIP) [n] y

    Parallel Printer support [y] y

3. Kernel message at startup

    lp1 at 0x0378, using polling driver
    .....
    NET3 PLIP version 2.0 [e-mail]
    plip2: Parallel port at 0x278, using assigned IRQ 5.

---end---

Again the standard disclaimer, like section 8.1.


__9__  A PLIP LINK BETWEEN DOS AND LINUX

After the first release of this Mini-HowTo many people wrote for info about
a link between Linux and DOS (or Windows) computer. The general interest
lead me to add this chapter, I hope will be of help to everybody.

This section comes from an article I've found on Linux Gazzette by James
McDuffie <[e-mail]> . It covers the basic installation of a PLIP
link between Linux and a DOS computer using Windows and Trumpet WinSock
and gives the address of a cool program that let's you run X-Windows
programs on Windows.

The next section is an addendum sent by James Vahn <[e-mail]>
where he describes deeply how to set up this link and how to solve many
problems.

I suppose you have already set up properly the PLIP support on the Linux
side and you have got the right cable, else go back to the previous chapters.

Now, for the DOS side, you need first of all a packet driver. It can be
found here:

ftp://ftp.crynwr.com/drivers/plip.zip

The program runs under DOS and acts like a Ethernet Packet driver.
If you want to use PLIP with Windows you need also Trumpet Winsock. This
serves as the TCP/IP interface. Otherwise, you can probably find TCP/IP
software for DOS.

Now go back to the Linux computer and add the DOS computer address to
/etc/hosts. If your DOS computer does not have a registered IP address
you may choose any address (remember the warning of chapter 3 about IP
addresses).

Now let's suppose you chose the name linux for the Linux computer and dos
for the DOS one. You have to type:

ifconfig plip1 linux pointopoint dos arp up
route add dos

Of course if you want to have this done every time you boot the linux
computer you may add these lines to the file /etc/rc.d/rc.inet1:

/sbin/ifconfig plip1 linux pointopoint dos arp up
/sbin/route add dos

This sets up the interface and then adds a route to it. Of course if you
are using the second parallel port you have to write plip2 instead.

Go back to the DOS/Windows computer and edit autoexec.bat, you have to
add the following lines.

c:\plip\plip.com 0x60
c:\tcpip\winsock\winpkt.com 0x60

Of course I suppose you put plip.com (the packet driver) in the directory
c:/plip and the winpkt.com in c:/tcpip, else you need to put the right path.

This sets the plip.com program on packet vector 0x60 and then loads the
winpkt.com program that comes with trumpet winsock on the same vector.
If the cable is something other than lpt1 you will have to tell plip.com
the irq number and io address. Also, winpkt.com needs to run to make the
packet vector avaliable to Windows. From here we go to the actual setup
under Trumpet Winsock. All you have to do is unselect SLIP or PPP and
enter 60 into the box labeled Packet vector. Then tell it the IP address
you gave it, the IP address of the Linux computer as the default gateway
and the Name Server as either you computer's ip or your ISP's address
for its nameservers if your going to connect it to the Internet (more on
this later). Close the setup and re-run Winsock and you should have it!
Put winsock in your startup group and you have everything setup automatically!

If you want to access the Internet through the Linux computer on the Windows
computer you will need to set up IP Masquerading, for info on this see the
NET-2-HOWTO. This simply masquerades the Windows computer with your Linux
computer's IP address.

Also I have found a program that lets you run X-Windows programs under
Windows! It is located at:

http://www.tucows.com/

Set it up according to directions and then all you have to do is telnet
in from the Windows computer then set the display to the Windows computer
(`DISPLAY=duncan:0.0` for instance) and run the program desired.
There is nothing cooler than running xv under Windows! Hope all this helped.

  _9.1_ A DOS-LINUX PLIP LINK EXPERIENCE.

NOTE: I received this document from James Vahn <[e-mail]> and
I put it here unchanged. This means that for any question about this section
he's much better qualified than me so please mail to him before to me.
His experience with a PLIP connection of a floppy-only DOS computer to a
Linux one is the perfect example of how to work-around common problems.

Last Update 11/07/1996 (dd/mm/yyyy format)
addendum from <[e-mail]>

My floppy-only DOS box is networked via PLIP to the second printer port on
the Linux machine. The first Linux printer port has a printer on it, both are
permanently connected and the DOS box is telnet'd into Linux. These are my
notes on what I did to accomplish this.

When the kernel probes for printer ports, it will grab all of them unless you
remove one from the probe. Otherwise PLIP will get nothing. One method is to
load the drivers as modules when needed...

<[e-mail]> writes:
=========================
I keep recommending using PLIP/LP as kernel module, since

    * modules are flexible for change of configuration
    * (re)compiling the kernel is not easy for novice users
    * co-existing PLIP and LP is only feasible by the modules

With PLIP/LP as kernel module, you can specify which port is PLIP and
which port is LP.  Here is example:

    # insmod lp.o io=0x378
    # insmod plip.o io=0x278 irq=2

Even you can use two parallel ports:

    # insmod plip.o io=0x278,0x3bc irq=2,5

In the example above,
plip0 is assigned on 0x278 and it's irq is 2,
plip1 is assigned on 0x3bc and it's irq is 5, respectively.

=========================

Using modules certainly sounds like the way to go. The following method shows
how to patch the kernel to allow both a printer and PLIP on different ports,
without modules. If you are unfamiliar with the module concept, you might
find this quicker to set up.

You will need to modify two files in the kernel source tree. I'm using kernel
1.2.13 and found some changes were needed in ../linux/drivers/net/Space.c to
accommodate my system. Look at around line 205 for the PLIP definitions to
make sure your port and IRQ match, and make a note of which driver it will be
(plip0, plip1, plip2). In my case port 0x278 uses IRQ 5 (the card is jumpered
that way) but Space.c defined it with IRQ 2. I made the changes here, rather
than opening up the box and changing jumpers. The alternative is to specify
the IRQ through ifconfig later on, but the kernel will boot up with the wrong
IRQ for PLIP and it may annoy you. It is a simple (single character) change.

The next, and more difficult step--
In .../drivers/char/lp.c you will find the following at around line 38:

struct lp_struct lp_table[] = {
    { 0x3bc, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL, NULL, },
    { 0x378, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL, NULL, },
/*  { 0x278, 0, 0, LP_INIT_CHAR, LP_INIT_TIME, LP_INIT_WAIT, NULL, NULL, },
 * 0x278 reserved for plip1
 *
 * };
 * #define LP_NO 3
 */
};
#define LP_NO 2

Notice the changes to make- one port is commented out, so now only 2 ports
are defined. Port 0x3BC will probably not work for PLIP- the IRQ line is
usually broken on these ports, as found on old monochrome adapters (MDA).

You made backups of these file before you changed them, right?  Now make a
new kernel with printer, net, dummy, and plip support.

Configure the system. This is my /etc/rc.d/rc.inet1 file:

#!/bin/bash
#
/sbin/ifconfig lo 127.0.0.1
/sbin/route add -net 127.0.0.0

/sbin/ifconfig dummy 200.0.0.1
/sbin/route add -net 200.0.0.0 netmask 255.255.255.0
/sbin/ifconfig plip1 arp 200.0.0.1 pointopoint 200.0.0.2 up
/sbin/route add 200.0.0.2
/sbin/ifconfig dummy down

Notice that arp is used for the DOS-to-Linux connection, apparently not used
on Linux-to-Linux connections.

And in /etc/hosts you can add these, just to give the two machines names:

200.0.0.1    console1
200.0.0.2    console2

The DOS box is console2. Note Andrea's warning about these, better to use
official numbering schemes.

Reboot so all of these changes and the new kernel will take effect. During
the boot sequence (or by running dmesg) if you made the patches, otherwise
when the modules are loaded:

lp0 at 0x03bc, using polling driver
lp1 at 0x0378, using polling driver
[....]
NET3 PLIP version 2.0 [e-mail]
plip1: Parallel port at 0x278, using assigned IRQ 5.

The "route" command shows this:

Kernel routing table
Destination     Gateway         Genmask         Flags MSS    Window Use Iface
console2        *               255.255.255.255 UH    1436   0      136 plip1
loopback        *               255.0.0.0       U     1936   0      109 lo

And "ifconfig plip1" shows:

plip1     Link encap:10Mbps Ethernet  HWaddr FC:FC:C8:00:00:01
          inet addr:200.0.0.1  P-t-P:200.0.0.2  Mask:255.255.255.0
          UP POINTOPOINT RUNNING  MTU:1500  Metric:1
          RX packets:132 errors:0 dropped:0 overruns:0
          TX packets:136 errors:0 dropped:0 overruns:0
          Interrupt:5 Base address:0x278

Look at /etc/inetd.conf and see if telnet is enabled. You might want to read
the man page for tcpd, and the use of /etc/hosts.allow (ALL: LOCAL) and
/etc/hosts.deny (ALL: ALL). You should be able to "telnet localhost".

Linux is done, now the DOS side. Again, be suspicious of port 0x3BC if one is
present.

I'm using NCSA's telnet and Crynwr's PLIP driver found at these sites:
ftp://ftp.ncsa.uiuc.edu/Telnet/DOS/ncsa/tel2308b.zip
ftp://ftp.crynwr.com/drivers/plip.zip

Be sure to use NCSA's version 2.3.08 telnet and version 11.1 of Crynwr's
PLIP driver. Please find and read Crynwr's SUPPORT.DOC located elswhere.

The CONFIG.TEL file.  Most of it is the default and to save some space
I've tried to cut it back here to just the info you need (hopefully). The
second port on this machine is setup as 0x278 on IRQ 5.

myip=200.0.0.2
netmask=255.255.255.0       # subnetting mask
hardware=packet             # network adapter board (packet driver interface)
interrupt=5                 # IRQ which adapter is set to
ioaddr=60                   # software interrupt vector driver is using
#
#[...lots unchanged...]
#
# at the end of the file, put this line:
name=console1 ; hostip=200.0.0.1 ; nameserver=1 ; gateway=1

(console1 is the name of the Linux machine, you can use whatever you like)

I made a 12 foot null cable between both machines, and (after initially
finding it miswired) there have been no problems. A standard 11-wire null
printer cable should work too. The Linux plip.c source shows the wiring.
Although my cable has the 17-17 connection, I don't think it is used for
anything and was not present on a ready-made cable.

@echo off
plip.com 0x60 5 0x278
telbin -s console1

That should connect you to the Linux box on /dev/ttyp. NCSA's telnet
provides for 8 virtual screens and also acts as an ftp server. The PLIP
interface provides a fair throughput, I'm getting 6.5K/s file transfers
with my antiques. Let's hope you can do better.  :-)

__10__ QUESTIONS? COMMENTS? SEND ME FEEDBACK

For any questions and comments you can find me via e-mail at the address
[e-mail]

Feedback is welcome, any error report is precious.
The next release should have a larger FAQ section, if you send questions.

__11__ WHERE TO FIND NEW RELEASES OF THIS MINI-HOWTO

This mini-HOWTO is maintained by the HOWTO coordinators and is posted
monthly on comp.os.linux.answers and can be found in the HOWTO directory
at sunsite and at sunsite's mirrors.

Another way to find the mini-HOWTO (and to contact me) is on my Home Page,

http://www.cli.di.unipi.it/~controzz/intro.html

__12__ CREDITS.

Many thanks to:

o Rick Lim <[e-mail]> for the patches to make PLIP
  and LP live together.

o Takeshi Okazaki <[e-mail]> for the patches to use PLIP
  and LP on two different parallel ports.

o Jim Van Zandt <[e-mail]> for some advice on the "tutorial" part
  of this HOWTO.

o James Vahn <[e-mail]> for the cool addendum on the PLIP
  between DOS and Linux chapter.

o To all the ones that posted PLIP-related articles on the linux newsgroups
  and/or mailed me. The list of all the people that helped me with info
  and comments could be longer than the Mini-HOWTO itself: thank you all!

__13__ COPYRIGHT MESSAGE

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