I'm looking in to how I can redirect an incoming telnet connection to go
out a serial port. What I'm trying to do is be able to telnet to a Slack
box, have the connection go out the serial port, and go to another (DOS)
box's serial port (via a null modem serial cable). That DOS box is
running a BBS program (PCBoard) which I'd like to make reachable over the
internet via telnet. As you may remember, DOS doesn't do TCP/IP, so
that's why this approach is being tried... Any ideas? Thanks.

Followups set to comp.os.linux.networking


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
"Bother!" said Pooh, as he garotted another passing Liberal.
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

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On 2009-10-10, Dan C <youmustbejoking@lan.invalid> wrote:
> I'm looking in to how I can redirect an incoming telnet connection to go
> out a serial port. What I'm trying to do is be able to telnet to a Slack
> box, have the connection go out the serial port, and go to another (DOS)
> box's serial port (via a null modem serial cable). That DOS box is
> running a BBS program (PCBoard) which I'd like to make reachable over the
> internet via telnet.

Well, perhaps the simplest solution is to setup a dedicated user for
this task, and set it's shell to run something like minicom or cu on
the serial port. Anytime the user logs in, rather than running bash or
what-not, minicom will fire up and contact the DOS box on that serial
port.

- --
It is better to hear the rebuke of the wise,
Than for a man to hear the song of fools.
Ecclesiastes 7:5
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On Mon, 12 Oct 2009 15:56:03 +0000, +Alan Hicks+ wrote:

>> I'm looking in to how I can redirect an incoming telnet connection to
>> go out a serial port. What I'm trying to do is be able to telnet to a
>> Slack box, have the connection go out the serial port, and go to
>> another (DOS) box's serial port (via a null modem serial cable). That
>> DOS box is running a BBS program (PCBoard) which I'd like to make
>> reachable over the internet via telnet.

> Well, perhaps the simplest solution is to setup a dedicated user for
> this task, and set it's shell to run something like minicom or cu on the
> serial port. Anytime the user logs in, rather than running bash or
> what-not, minicom will fire up and contact the DOS box on that serial
> port.

Not a bad idea, but won't work as far as making a BBS accessible to the
public (many different users, names unknown).

I'm exploring the world of networking on MSDOS, when I have some free
time. It's an ugly thing, to be sure.


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
"Bother!" said Pooh, as he garotted another passing Liberal.
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

Dan C <youmustbejoking@lan.invalid> wrote:
>> Well, perhaps the simplest solution is to setup a dedicated user for
>> this task, and set it's shell to run something like minicom
>> or cu on the serial port. Anytime the user logs in, rather than running
>> bash or what-not, minicom will fire up and contact the DOS box on that
>> serial port.
>
> Not a bad idea, but won't work as far as making a BBS accessible to the
> public (many different users, names unknown).

I understand that is why you want to redirect telnet to the serial port.
That way the BBS software will take care of user login. However, there is
a big difference when it comes to security if you compare telnet and a
modem. It is rather easy to listen on the traffic of an unencrypted telnet
connection. Somehow you would be better off with an encrypted ssh
connection, but I don't know how to let the BBS software handle the
username and password with ssh.

regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc3(at)poolhem.se Examples of addresses which go to spammers:
root@localhost postmaster@localhost

On 2009-10-13, Henrik Carlqvist <Henrik.Carlqvist@deadspam.com> wrote:
> Dan C <youmustbejoking@lan.invalid> wrote:
>>> Well, perhaps the simplest solution is to setup a dedicated user for
>>> this task, and set it's shell to run something like minicom
>>> or cu on the serial port. Anytime the user logs in, rather than running
>>> bash or what-not, minicom will fire up and contact the DOS box on that
>>> serial port.
>>
>> Not a bad idea, but won't work as far as making a BBS accessible to the
>> public (many different users, names unknown).
>
> I understand that is why you want to redirect telnet to the serial port.
> That way the BBS software will take care of user login. However, there is
> a big difference when it comes to security if you compare telnet and a
> modem. It is rather easy to listen on the traffic of an unencrypted telnet
> connection. Somehow you would be better off with an encrypted ssh
> connection, but I don't know how to let the BBS software handle the
> username and password with ssh.

hmm interesting idea. perhaps theres a way to point PAM at the BBSs
user database, OTOH you could set up a user 'bbs' with no password and
just connect them the BBS.

using SSH forces the users to use something better than windows'
rubbish telent client, something like "putty" for instance. but then
raises the issue that you'll need something to convert BBS-ANSI to
VT220, perhaps there's a way to do that using minicom?

On Tue, 13 Oct 2009 09:14:37 +0200, Henrik Carlqvist wrote:

> ... Somehow you would be better off with an encrypted ssh connection,
> but I don't know how to let the BBS software handle the username and
> password with ssh.

The BBS doesn't. All it sees is the serial connection to the networked
host. The Ssh connection is between the client and the network facing
"gateway" to the BBS. It could work, of course. Login as user "bbs"
(or whatever), with no password; that user's "shell" fires up a
connection via the serial port to the actual BBS (complain and exit if
such a connection is already in place?); the BBS does the actual user
authentication according to its own user data. The traffic encryption
stops at the Linux box.

--
----------------------------------------------------------------------
Sylvain Robitaille syl@encs.concordia.ca

Systems analyst / AITS Concordia University
Faculty of Engineering and Computer Science Montreal, Quebec, Canada
----------------------------------------------------------------------

On Tue, 13 Oct 2009 19:43:26 +0000, Sylvain Robitaille wrote:

> On Tue, 13 Oct 2009 09:14:37 +0200, Henrik Carlqvist wrote:
>
>> ... Somehow you would be better off with an encrypted ssh connection,
>> but I don't know how to let the BBS software handle the username and
>> password with ssh.
>
> The BBS doesn't. All it sees is the serial connection to the networked
> host. The Ssh connection is between the client and the network facing
> "gateway" to the BBS. It could work, of course. Login as user "bbs"
> (or whatever), with no password; that user's "shell" fires up a
> connection via the serial port to the actual BBS (complain and exit if
> such a connection is already in place?); the BBS does the actual user
> authentication according to its own user data. The traffic encryption
> stops at the Linux box.

This sounds like it could work, and would serve my needs just fine. The
tricky part is getting the communication from the Linux gateway to the
DOS computer running the BBS. How to connect the "bbs" user to the
outbound serial port of the Linux box? After that, a null modem serial
cable over to the BBS box should work. I'd surely like some specifics on
how to make this shell/serial port connection on the Linux box, if anyone
has any insights.

Thanks.


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
"Bother!" said Pooh, as he garotted another passing Liberal.
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

On Wednesday 14 October 2009 01:04 in alt.os.linux, somebody identifying
as Dan C wrote...

> On Tue, 13 Oct 2009 19:43:26 +0000, Sylvain Robitaille wrote:
>
>> On Tue, 13 Oct 2009 09:14:37 +0200, Henrik Carlqvist wrote:
>>
>>> ... Somehow you would be better off with an encrypted ssh
>>> connection, but I don't know how to let the BBS software handle the
>>> username and password with ssh.
>>
>> The BBS doesn't. All it sees is the serial connection to the
>> networked host. The Ssh connection is between the client and the
>> network facing "gateway" to the BBS. It could work, of course.
>> Login as user "bbs" (or whatever), with no password; that
>> user's "shell" fires up a connection via the serial port to the
>> actual BBS (complain and exit if such a connection is already in
>> place?); the BBS does the actual user authentication according to its
>> own user data. The traffic encryption stops at the Linux box.
>
> This sounds like it could work, and would serve my needs just fine.
> The tricky part is getting the communication from the Linux gateway to
> the DOS computer running the BBS. How to connect the "bbs" user to
> the outbound serial port of the Linux box? After that, a null modem
> serial cable over to the BBS box should work. I'd surely like some
> specifics on how to make this shell/serial port connection on the
> Linux box, if anyone has any insights.

Well, a couple of posters have suggested using /netcat/ for that
purpose, and from reading the /man/ page on it, I believe that this
should work just as you want it to.

The other option, which I would not rule out just yet, would be to
implement TCP/IP on the DOS box. Now I don't know what DOS version
you're running on that machine, but if possible, I would recommend
FreeDOS. It's more modern than a MICROS~1, IBM or DR DOS, it's free -
as in GPL'ed, and thus with the source code available - and by looking
at the FreeDOS website, it should be easier to implement TCP/IP on it
than on any of the aforementioned proprietary DOS versions.

There's also a far greater chance of finding a NIC that's supported
natively in FreeDOS, although the ubiquitous Realtek 8139 and some of
the more popular 10/100 3Coms do come with DOS-native drivers supplied
by the vendor on either a floppy disk or on a CD-ROM, of course. But
just in the event that you don't have such a driver disk, given that
those popular NICs are supported by default in the Linux kernel and
that FreeDOS is GPL'ed, I suspect that it has those drivers already "in
it" (as loadable device drivers via CONFIG.SYS) out of the box.

I am interested in this project of yours because I have an old Pentium
MMX 200 MHz box with 32 MB of EDO RAM and a 1.3 GB Seagate IDE hard
disk sitting here idle in which I have stuffed a Realtek 8139 NIC and
of which I have been contemplating putting it to use with FreeDOS in
some way. As old as that box may be - and I even got it for free! -
its hardware still seems to be in perfect shape, and that is more than
I can say of some very dearly paid newer machines I've purchased all
over the years. So if the hardware is reliable, then it would be a
shame not to use it, and given the low specs of the machine, FreeDOS
would be a perfect choice.

Now I don't have any experience whatsoever with a BBS - never used them
and never set one up - but that in itself might also already seem like
a nice implementation, just for the heck of it. ;-)

(Follow-ups set to alt.os.linux and comp.os.linux.networking because I'm
not in the Slackware group and KNode won't let me post to three groups
without setting a follow-up. Feel free to change as desired if need
be, but please keep the thread crossposted to the non-Slack groups so I
can keep monitoring the thread. :p)

--
*Aragorn*
(registered GNU/Linux user #223157)

On Wed, 14 Oct 2009 03:33:05 +0200, Aragorn wrote:

> On Wednesday 14 October 2009 01:04 in alt.os.linux, somebody identifying
> as Dan C wrote...
>
>> On Tue, 13 Oct 2009 19:43:26 +0000, Sylvain Robitaille wrote:
>>
>>> On Tue, 13 Oct 2009 09:14:37 +0200, Henrik Carlqvist wrote:
>>>
>>>> ... Somehow you would be better off with an encrypted ssh connection,
>>>> but I don't know how to let the BBS software handle the username and
>>>> password with ssh.
>>>
>>> The BBS doesn't. All it sees is the serial connection to the
>>> networked host. The Ssh connection is between the client and the
>>> network facing "gateway" to the BBS. It could work, of course. Login
>>> as user "bbs" (or whatever), with no password; that user's "shell"
>>> fires up a connection via the serial port to the actual BBS (complain
>>> and exit if such a connection is already in place?); the BBS does the
>>> actual user authentication according to its own user data. The
>>> traffic encryption stops at the Linux box.
>>
>> This sounds like it could work, and would serve my needs just fine. The
>> tricky part is getting the communication from the Linux gateway to the
>> DOS computer running the BBS. How to connect the "bbs" user to the
>> outbound serial port of the Linux box? After that, a null modem serial
>> cable over to the BBS box should work. I'd surely like some specifics
>> on how to make this shell/serial port connection on the Linux box, if
>> anyone has any insights.
>
> Well, a couple of posters have suggested using /netcat/ for that
> purpose, and from reading the /man/ page on it, I believe that this
> should work just as you want it to.
>
> The other option, which I would not rule out just yet, would be to
> implement TCP/IP on the DOS box. Now I don't know what DOS version
> you're running on that machine, but if possible, I would recommend
> FreeDOS. It's more modern than a MICROS~1, IBM or DR DOS, it's free -
> as in GPL'ed, and thus with the source code available - and by looking
> at the FreeDOS website, it should be easier to implement TCP/IP on it
> than on any of the aforementioned proprietary DOS versions.
>
> There's also a far greater chance of finding a NIC that's supported
> natively in FreeDOS, although the ubiquitous Realtek 8139 and some of
> the more popular 10/100 3Coms do come with DOS-native drivers supplied
> by the vendor on either a floppy disk or on a CD-ROM, of course. But
> just in the event that you don't have such a driver disk, given that
> those popular NICs are supported by default in the Linux kernel and that
> FreeDOS is GPL'ed, I suspect that it has those drivers already "in it"
> (as loadable device drivers via CONFIG.SYS) out of the box.
>
> I am interested in this project of yours because I have an old Pentium
> MMX 200 MHz box with 32 MB of EDO RAM and a 1.3 GB Seagate IDE hard disk
> sitting here idle in which I have stuffed a Realtek 8139 NIC and of
> which I have been contemplating putting it to use with FreeDOS in some
> way. As old as that box may be - and I even got it for free! - its
> hardware still seems to be in perfect shape, and that is more than I can
> say of some very dearly paid newer machines I've purchased all over the
> years. So if the hardware is reliable, then it would be a shame not to
> use it, and given the low specs of the machine, FreeDOS would be a
> perfect choice.
>
> Now I don't have any experience whatsoever with a BBS - never used them
> and never set one up - but that in itself might also already seem like a
> nice implementation, just for the heck of it. ;-)
>
> (Follow-ups set to alt.os.linux and comp.os.linux.networking because I'm
> not in the Slackware group and KNode won't let me post to three groups
> without setting a follow-up. Feel free to change as desired if need be,
> but please keep the thread crossposted to the non-Slack groups so I can
> keep monitoring the thread. :p)

Thanks for the reply. I'm quite interested in the 'netcat' approach and
am going to give that a try. Also have been scouring and collecting old
files for attempting to get TCP/IP on the DOS box. It has an old SMC
(8614) NIC in it that seems to be supported by some of the packet driver
software I've found.

Problem right now is being busy with work and Real Life, and won't have
any time for this until the weekend (if then). I will report on any
progress I make as I go along.

BTW, the DOS box I'm using has a 486DX4/100 CPU and a 420MB HD. Can't
recall how much RAM, but I think it's 4MB... ;) Runs DOS like a dream.
Currently have MSDOS 6.22 on there, and may pursue the FreeDOS avenue if
things don't play nice.

Thanks again for the input, and stay tuned...


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
"Bother!" said Pooh, as he garotted another passing Liberal.
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

On 13 Oct 2009 23:04:28 GMT, Dan C wrote:

> ... The tricky part is getting the communication from the Linux
> gateway to the DOS computer running the BBS. How to connect the "bbs"
> user to the outbound serial port of the Linux box? ...

Look at the "cu" command from the UUCP package that ships with Slackware.
I think you *should* be able to set that up, with appropriate options
as your "bbs" user's shell, to have anyone logging into your system with
that be immediately captive to the serial connection to the BBS system.

I hope this helps ...

--
----------------------------------------------------------------------
Sylvain Robitaille syl@encs.concordia.ca

Systems analyst / AITS Concordia University
Faculty of Engineering and Computer Science Montreal, Quebec, Canada
----------------------------------------------------------------------

On Wed, 14 Oct 2009 05:17:43 +0000, Sylvain Robitaille wrote:

> On 13 Oct 2009 23:04:28 GMT, Dan C wrote:
>
>> ... The tricky part is getting the communication from the Linux gateway
>> to the DOS computer running the BBS. How to connect the "bbs" user to
>> the outbound serial port of the Linux box? ...
>
> Look at the "cu" command from the UUCP package that ships with
> Slackware. I think you *should* be able to set that up, with appropriate
> options as your "bbs" user's shell, to have anyone logging into your
> system with that be immediately captive to the serial connection to the
> BBS system.
>
> I hope this helps ...

Excellent! That looks very promising. Now to just find some time for
all this... Hopefully on the weekend. Thanks a lot for the info.


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
"Bother!" said Pooh, as he garotted another passing Liberal.
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

Dan C wrote:
> On Wed, 14 Oct 2009 03:33:05 +0200, Aragorn wrote:
>
>> On Wednesday 14 October 2009 01:04 in alt.os.linux, somebody identifying
>> as Dan C wrote...
>>
>>> On Tue, 13 Oct 2009 19:43:26 +0000, Sylvain Robitaille wrote:
>>>
>>>> On Tue, 13 Oct 2009 09:14:37 +0200, Henrik Carlqvist wrote:
>>>>
>>>>> ... Somehow you would be better off with an encrypted ssh connection,
>>>>> but I don't know how to let the BBS software handle the username and
>>>>> password with ssh.
>>>> The BBS doesn't. All it sees is the serial connection to the
>>>> networked host. The Ssh connection is between the client and the
>>>> network facing "gateway" to the BBS. It could work, of course. Login
>>>> as user "bbs" (or whatever), with no password; that user's "shell"
>>>> fires up a connection via the serial port to the actual BBS (complain
>>>> and exit if such a connection is already in place?); the BBS does the
>>>> actual user authentication according to its own user data. The
>>>> traffic encryption stops at the Linux box.
>>> This sounds like it could work, and would serve my needs just fine. The
>>> tricky part is getting the communication from the Linux gateway to the
>>> DOS computer running the BBS. How to connect the "bbs" user to the
>>> outbound serial port of the Linux box? After that, a null modem serial
>>> cable over to the BBS box should work. I'd surely like some specifics
>>> on how to make this shell/serial port connection on the Linux box, if
>>> anyone has any insights.
>> Well, a couple of posters have suggested using /netcat/ for that
>> purpose, and from reading the /man/ page on it, I believe that this
>> should work just as you want it to.
>>
>> The other option, which I would not rule out just yet, would be to
>> implement TCP/IP on the DOS box. Now I don't know what DOS version
>> you're running on that machine, but if possible, I would recommend
>> FreeDOS. It's more modern than a MICROS~1, IBM or DR DOS, it's free -
>> as in GPL'ed, and thus with the source code available - and by looking
>> at the FreeDOS website, it should be easier to implement TCP/IP on it
>> than on any of the aforementioned proprietary DOS versions.
>>
>> There's also a far greater chance of finding a NIC that's supported
>> natively in FreeDOS, although the ubiquitous Realtek 8139 and some of
>> the more popular 10/100 3Coms do come with DOS-native drivers supplied
>> by the vendor on either a floppy disk or on a CD-ROM, of course. But
>> just in the event that you don't have such a driver disk, given that
>> those popular NICs are supported by default in the Linux kernel and that
>> FreeDOS is GPL'ed, I suspect that it has those drivers already "in it"
>> (as loadable device drivers via CONFIG.SYS) out of the box.
>>
>> I am interested in this project of yours because I have an old Pentium
>> MMX 200 MHz box with 32 MB of EDO RAM and a 1.3 GB Seagate IDE hard disk
>> sitting here idle in which I have stuffed a Realtek 8139 NIC and of
>> which I have been contemplating putting it to use with FreeDOS in some
>> way. As old as that box may be - and I even got it for free! - its
>> hardware still seems to be in perfect shape, and that is more than I can
>> say of some very dearly paid newer machines I've purchased all over the
>> years. So if the hardware is reliable, then it would be a shame not to
>> use it, and given the low specs of the machine, FreeDOS would be a
>> perfect choice.
>>
>> Now I don't have any experience whatsoever with a BBS - never used them
>> and never set one up - but that in itself might also already seem like a
>> nice implementation, just for the heck of it. ;-)
>>
>> (Follow-ups set to alt.os.linux and comp.os.linux.networking because I'm
>> not in the Slackware group and KNode won't let me post to three groups
>> without setting a follow-up. Feel free to change as desired if need be,
>> but please keep the thread crossposted to the non-Slack groups so I can
>> keep monitoring the thread. :p)
>
> Thanks for the reply. I'm quite interested in the 'netcat' approach and
> am going to give that a try. Also have been scouring and collecting old
> files for attempting to get TCP/IP on the DOS box. It has an old SMC
> (8614) NIC in it that seems to be supported by some of the packet driver
> software I've found.
>
> Problem right now is being busy with work and Real Life, and won't have
> any time for this until the weekend (if then). I will report on any
> progress I make as I go along.
>
> BTW, the DOS box I'm using has a 486DX4/100 CPU and a 420MB HD. Can't
> recall how much RAM, but I think it's 4MB... ;) Runs DOS like a dream.
> Currently have MSDOS 6.22 on there, and may pursue the FreeDOS avenue if
> things don't play nice.
>
> Thanks again for the input, and stay tuned...
>
>
You should look for an old SMC 8303 series, Ungerman-Bass, or a 3C509
TP. Most old DOS versions support these cards. I am running a PS/2
486SLC-2 with PC-DOS and an SMC 8303/A at 10mbps.

On 14 Oct 2009 03:21:56 GMT,
Dan C <youmustbejoking@lan.invalid> wrote:
> On Wed, 14 Oct 2009 03:33:05 +0200, Aragorn wrote:

>> The other option, which I would not rule out just yet, would be
>> to implement TCP/IP on the DOS box.

> ...have been scouring and collecting old files for
> attempting to get TCP/IP on the DOS box.

Dan, this approach might be possible. Back around the turn of the
millenium I used an HP 200LX as my sole travel computer. It ran
DOS 5.0, and with lots of niggling I was able to get it connected
to the internet with TCP/IP over an ethernet PCMCIA card as well
as with a modem. Some of my old notes from those activities (not
all of which is relevant to your request) are here:

http://heise.nu/LXTCP.html

http://heise.nu/LX-LAN.html

The starting point would probably be WATTCP. There is at least
one caveat, this was all done using the 200LX as a client, but it
seems if you could get a TCP/IP connection established, it might
be possible to use the box to serve up services. I do have some
dim memory of using ssh to login to the 200LX over the network.

--
Theodore (Ted) Heise <theo@heise.nu> Bloomington, IN, USA

On Thu, 15 Oct 2009 07:15:54 -0400, Theodore Heise wrote:

> On 14 Oct 2009 03:21:56 GMT,
> Dan C <youmustbejoking@lan.invalid> wrote:
>> On Wed, 14 Oct 2009 03:33:05 +0200, Aragorn wrote:
>
>>> The other option, which I would not rule out just yet, would be to
>>> implement TCP/IP on the DOS box.
>
>> ...have been scouring and collecting old files for
>> attempting to get TCP/IP on the DOS box.
>
> Dan, this approach might be possible. Back around the turn of the
> millenium I used an HP 200LX as my sole travel computer. It ran DOS
> 5.0, and with lots of niggling I was able to get it connected to the
> internet with TCP/IP over an ethernet PCMCIA card as well as with a
> modem. Some of my old notes from those activities (not all of which is
> relevant to your request) are here:
>
> http://heise.nu/LXTCP.html
>
> http://heise.nu/LX-LAN.html
>
> The starting point would probably be WATTCP. There is at least one
> caveat, this was all done using the 200LX as a client, but it seems if
> you could get a TCP/IP connection established, it might be possible to
> use the box to serve up services. I do have some dim memory of using
> ssh to login to the 200LX over the network.

Good stuff. Really appreciate the input.


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
"Bother!" said Pooh, as he garotted another passing Liberal.
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

On Wed, 14 Oct 2009 03:33:05 +0200, Aragorn wrote:
> The other option, which I would not rule out just yet, would be to
> implement TCP/IP on the DOS box.

Go take a look at FreeDOS and their networking documentation. They have
quite a bit of good information on networking in DOS. Further, FreeDOS
its self, is using a lot of open source programs that have been compiled
for DOS.

Link - FreeDOS Networking
- http://www.freedos.org/freedos/news/technote/157.html



Grant. . . .