help with using dip over a null modem

help with using dip over a null modem

Post by Dennis Jenki » Thu, 02 Nov 1995 04:00:00



In the first place, I know that DIP is overkill, but that's the only
thing that I've been able to get to work so far.  I have a 486 Linux box
and a 286 dos box.  I link the dos box to the linux box over a null modem
cable.  I run the connection at 115200 baud (never had any problems at
that speed.  too bad there's nothing faster (well, I could get an
ethernet card for the 286, but those cost $$)).  I want to run CSLIP on
this connection.  so far I've been able to use DIP to set it up and it
works fine, until...
                 shut off the 286.  DIP on the linux end sees the
connection go down and un-installs itself.  It never starts back up.  If
I put a respawning line in my inittab for a script that runs dip, dip
will run about 20 times all at once and the 2nd-19th will bomb with an
'device locked' message, and it doesn't respawn correctly anyway.  What
I'm looking for is a way to either 1) get DIP to be immortal, or
2(better) ) use a different method for setting up the connection.
        Regardless of what I use, keep in mind that the 286 and 486 get
turned on and off, and not always at the same time, and occasionally, the
286 will be used for things other than SLIP (and I don't want the SLIP
connection on the linux box to die).
        A friend said to use slattach, route and ifconfig, but I'ver been
unsuccessful at my attempts with those.
        My Linux box (not on the 'real' internet) has the IP 172.16.83.3,
and uses /dev/cua1 for the null modem line.  The 286 (everything works on
this end, under DOS), uses COM1: for the null modem and I want it to have
the IP 172.16.83.129.
        Any help would be appreciated.

--

Gamma Lambda 204 of Pi Kappa Phi        http://www.umr.edu/~pikapps
"May he go forth in the sunrise boat,  May he come to port in the sunset
boat, May he go among the imperishable stars,  May he journey in the
Boat of a Million Years." -Going Forth by Daylight, Theban Recension, 18DYN.
The Code:  GCS d-- H s+:- !g p? !au a-- w+ v-- C++++ ULHS+++ P? L++> !3
           E---- N++ K- W--- M+ V-- -po+ Y+ t+++ 5+++ j R-> G'' tv+++ b+
           D+++ (D---) B--- e+>>> u h++ f+ !r n---- y?

 
 
 

help with using dip over a null modem

Post by Jens Dav » Mon, 06 Nov 1995 04:00:00



Quote:

>In the first place, I know that DIP is overkill, but that's the only
>thing that I've been able to get to work so far.  I have a 486 Linux box
>and a 286 dos box.  I link the dos box to the linux box over a null modem
>cable.  I run the connection at 115200 baud (never had any problems at
>that speed.  too bad there's nothing faster (well, I could get an
>ethernet card for the 286, but those cost $$)).  I want to run CSLIP on
>this connection.  so far I've been able to use DIP to set it up and it
>works fine, until...
>                 shut off the 286.  DIP on the linux end sees the
>connection go down and un-installs itself.  It never starts back up.  If
>I put a respawning line in my inittab for a script that runs dip, dip
>will run about 20 times all at once and the 2nd-19th will bomb with an
>'device locked' message, and it doesn't respawn correctly anyway.  What
>I'm looking for is a way to either 1) get DIP to be immortal, or
>2(better) ) use a different method for setting up the connection.
>        Regardless of what I use, keep in mind that the 286 and 486 get
>turned on and off, and not always at the same time, and occasionally, the
>286 will be used for things other than SLIP (and I don't want the SLIP
>connection on the linux box to die).
>        A friend said to use slattach, route and ifconfig, but I'ver been
>unsuccessful at my attempts with those.
>        My Linux box (not on the 'real' internet) has the IP 172.16.83.3,
>and uses /dev/cua1 for the null modem line.  The 286 (everything works on
>this end, under DOS), uses COM1: for the null modem and I want it to have
>the IP 172.16.83.129.
>        Any help would be appreciated.

On the linux box:

slattach -s19200 -pslip /dev/ttyS1
ifconfig sl0 172.16.83.3 pointopoint 172.16.83.129 up
route add -host 172.16.83.129 sl0

There's no reason why slattach should be killed when you turn the power off
on the 286. In any case, FORGET DIP.

If you want to put the above lines in your /etc/rc.d/rc.inet1 please don't
forget to run slattach in the backgroud ("&") because otherwise it'll block
the whole boot process.

Hope I could help you with this.

>--

>Gamma Lambda 204 of Pi Kappa Phi        http://www.umr.edu/~pikapps
>"May he go forth in the sunrise boat,  May he come to port in the sunset
>boat, May he go among the imperishable stars,  May he journey in the
>Boat of a Million Years." -Going Forth by Daylight, Theban Recension, 18DYN.
>The Code:  GCS d-- H s+:- !g p? !au a-- w+ v-- C++++ ULHS+++ P? L++> !3
>           E---- N++ K- W--- M+ V-- -po+ Y+ t+++ 5+++ j R-> G'' tv+++ b+
>           D+++ (D---) B--- e+>>> u h++ f+ !r n---- y?

byebye,
   Jens

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



============================================================================
"The single most brilliant design decision in all of UNIX was the
 choice of a SINGLE character as the end-of-line indicator" -- M. O'Dell
 "Whoever picked the end-of-line conventions for MS-DOS and the Macintosh
 should be shot!" -- Phil Karn's corollary to O'Dell's declaration
============================================================================

 
 
 

help with using dip over a null modem

Post by Raj Math » Sun, 12 Nov 1995 04:00:00


Dslip seems to work pretty well in these scenarios. Adding the -c flag
to dudiscdev helps in maintaining the link.

Look in system/Network/serial at a sunsite mirror for dslip.

-- Raj
#include <std_disclaimer.h>

    Dennis> In the first place, I know that DIP is overkill, but
    Dennis> that's the only thing that I've been able to get to work
    Dennis> so far. I have a 486 Linux box and a 286 dos box. I link
    Dennis> the dos box to the linux box over a null modem cable. I
    Dennis> run the connection at 115200 baud (never had any problems
    Dennis> at that speed. too bad there's nothing faster (well, I
    Dennis> could get an ethernet card for the 286, but those cost
    Dennis> $$)). I want to run CSLIP on this connection. so far I've
    Dennis> been able to use DIP to set it up and it works fine,
    Dennis> until... shut off the 286. DIP on the linux end sees the
    Dennis> connection go down and un-installs itself. It never starts
    Dennis> back up. If I put a respawning line in my inittab for a
    Dennis> script that runs dip, dip will run about 20 times all at
    Dennis> once and the 2nd-19th will bomb with an 'device locked'
    Dennis> message, and it doesn't respawn correctly anyway. What I'm
    Dennis> looking for is a way to either 1) get DIP to be immortal,
    Dennis> or 2(better) ) use a different method for setting up the
    Dennis> connection. Regardless of what I use, keep in mind that
    Dennis> the 286 and 486 get turned on and off, and not always at
    Dennis> the same time, and occasionally, the 286 will be used for
    Dennis> things other than SLIP (and I don't want the SLIP
    Dennis> connection on the linux box to die). A friend said to use
    Dennis> slattach, route and ifconfig, but I'ver been unsuccessful
    Dennis> at my attempts with those. My Linux box (not on the 'real'
    Dennis> internet) has the IP 172.16.83.3, and uses /dev/cua1 for
    Dennis> the null modem line. The 286 (everything works on this
    Dennis> end, under DOS), uses COM1: for the null modem and I want
    Dennis> it to have the IP 172.16.83.129. Any help would be
    Dennis> appreciated.
--

PGP: C6 3A 1A 93 DE 08 DA 65  / Ph: 91-11-3317583  / Fax: 3317583

                      It is the mind that moves.

 
 
 

help with using dip over a null modem

Post by Greg de Freita » Tue, 14 Nov 1995 04:00:00


Try diald:
Diald is a daemon that does demand dialing for PPP and SLIP.
The purpose of diald is to make it transparently appear that you
have a permanent connection to a remote site. Diald sets up a "proxy"
device which stands in for the physical connection to a remote site.
It then monitors the proxy, waiting for packets to arrive. When interesting
packets arrive it will attempt to establish the physical link to the remote
site using either SLIP or PPP, and if it succeeds it will forward traffic
from the proxy to the physical link. As well, diald will monitor
traffic once the physical link is up, and when it has determined
that the link is idle, the remote connection is terminated. The
criteria for bringing the link up and taking it down are configurable
at run time, and are based upon the type of traffic passing over the link.

Diald is now in BETA release. When I stop adding features from the
wish list and a sufficient time interval passes I'll change
the release number to 1.0 and put it into production release.
At that time I plan start work on a redesigned second generation diald.

WHERE TO GET IT
---------------
The file is called diald-0.11.tar.gz.
I've uploaded it to sunsite.unc.edu:/pub/Linux/Incoming.
It should move to sunsite.unc.edu:/pub/Linux/system/Network/serial
after a suitable interval.

MAILING LIST
------------

David S. Miller is providing a mailing for the discussion of diald
on his Majordomo server at vger.rutgers.edu.
Send mail containing the line "subscribe linux-diald" in the BODY

Send mail with the word "help" in the body to get help on the
correct use of the Majordomo list server. Announcements of
new releases are made on the mailing list, and its a good place
to ask questions of users who already have diald up and running.
I would prefer the mailing list to be my primary channel of communication
with users. This gives you the added benifit of asking your questions
of everyone on the list, many of whom may have the same question, or
some of who may have already solved your problem. This miminizes the
time I have to spend answering questions about diald, and gives me
more time to spend improving the program.


Copies of the archive can be obtained at ftp://rex.isdn.net/pub/diald.
Currently the archives are updated once a month.

FAQ
---
There is a copy of the full FAQ distributed with this release.

volunteered to maintain the FAQ for diald. If you have
trouble getting started with diald, and you don't find
your answer in the existing FAQ, please consider contributing
to the FAQ once you get your questions answered. You can

(Please don't send them directly to Gordon he's using a semi
automated process and we don't want to mess it up.)

BEFORE INSTALLATION
-------------------
You must have SLIP devices in your kernel in order to use diald,
EVEN IF YOU PLAN TO USE ONLY PPP CONNECTIONS! Let me repeat that,
diald needs SLIP to work under all circumstances. It uses a SLIP
link on a pseudo terminal to create the proxy device that stands
in for the real connection. Naturally, if you plan on using diald
to establish PPP connections, you must also have PPP devices in your
kernel. You must also have a program like "chat" to do dialing.
Also, if you plan to have a lot of diald's running around (connecting
to different sites) you will probably need to increase the number of
SLIP and possibly PPP devices in your kernel. Note that diald takes
up one SLIP device for every connection whether it is active or not,
and one PPP device for every connection that is currently active.

CONFIGURING DIALD
-----------------
Various pathnames that diald needs to know can be configured in "config.h".
Edit this file appropriately. The eventual installation location for the
diald binary, the man page and the diald definitions file can be configured
in the Makefile.
If you are using pppd version 2.2.0, then you MUST set the flag
"PPP_VERSION_2_2_0 in the configuration file. If you upgrade
to pppd 2.2.0 then you will have to recompile diald with this
flag defined before diald will work again.

BASIC INSTALLATION (FIRST TIME USERS)
-------------------------------------
WARNING: Don't do this if you are already running a previous version of
diald, it will destroy your existing configuration files!

First run "make depend" then "make" and then "make install" as root.
This makes the diald daemon and installs it. Next run "make install-configs".
This will install the the configuration files /etc/diald.defs and
/etc/diald.conf. After installation you probably want to edit /etc/diald.conf
to customize diald to your local site. Read the manual page to find out
what this file can contain.

INSTALLATION IF YOU ARE ALREADY USING AN EARLIER VERSION
--------------------------------------------------------
Run "make depend" then "make" and then "make install" as root
to install the new executable and man page.
If you don't want to save an existing /etc/diald.conf
file just proceed as for the basic first time installation.
Otherwise, you must copy the doc/diald.defs file to /etc/diald.defs by hand.
This file contains the definitions of protocol rules and variable
names used by the filter definitions. YOU MUST HAVE IT INSTALLED.
If you want to use an old /etc/diald.conf file you will need to
update some of the contents as the names and means of various commands
have evolved a little over time. In particular a major change in
syntax took place between version 0.3 and 0.4 and a change in semantics
took place between version 0.7 and 0.8.
See the CHANGES file for more information.

USING DIALD
-----------
Read the man page for more information.

BUGS & LIMITATIONS
------------------
There are some known problems and limitations.

Lines in options files can contain at most 1024 characters.
Longer lines are silently truncated.

If there are no filter rules specified then no packets
will be matched and the daemon won't do anything. It
should probably match all packets by default in this case.

Diald's support for multiple modem devices is somewhat
limited. It will try a list of devices, but it uses the
same chat script and control settings on all the devices.
This means that you must have the same kind of modem on
every device. At some point diald needs a better way to
configure individual devices for call out in an independent way.

Diald has no way of automatically adjusting the MTU of the
proxy to match the MTU of the actual connection negotiated
by ppp. If these values do not match then long packets
will be dropped on the floor. You must match these values
manually. Use ifconfig to find out what MTU was negotiated
by ppp once the link comes up.
This won't be fixed until Alan Cox gets the TCP stack
fixed so that it can deal with MTU changes. As far as I know
it's on his list of things to do, but don't hold your breath,
I'm sure he's got a lot to do.

Please send bug reports, patches or suggestions for improvements to me,
preferably via the mailing list.

Eric Schenk

Toronto, Canada, October 15th, 1995.

--
Ciao 4 now,
Greg.
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