[BL] serial networking and telnet server

sindi keesan keesan at sdf.lonestar.org
Wed Oct 20 00:30:38 EDT 2004


On Wed, 20 Oct 2004 3aoo-cvfd at dea.spamcon.org wrote:

> sindi keesan wrote:
>>
>> I have been reading various HOWTOs and web pages.
>> THere is also slip, cslip, dip and slattach and wvdial
>> and linuxconf to set up ppp
>
> That is not correct.  slattach has nothing to do with
> ppp.  It is an alternative method of putting a TCP/IP
> network on a serial line.  slattach uses slip (or cslip)
> but not ppp.
>
>> but I found one suggestion to use ifconfig.
>
> ifconfig is used for slattach, not ppp.

There were a lot of conflicting instructions about how to establish a 
serial connection.

>> Is there some way to set this up so as not to need
>> login and password?
>
> For telnet?  The purpose of telnet is to enable you
> to login to the system like a local user.

I can set up a script to enter these automatically with PCPlus or Kermit 
and probably with other dialing programs.  I can even automatically enter 
user name when telnetting with kermit.  How would I do this for a local 
serial connection via dumb terminal or ppp?

>
>> With ethernet I did not need either to send files.
>
> That was using the send/receive scripts.  They will also
> work via ppp.

I was able to use these, slowly.

>> I was reading about putting the IP address of the incoming
>> computer into pap-secrets so that authentication would not
>> be required
>
> Are you still talking about telnet authentication?  If so,
> the above has nothing to do with it.

So how would I set up telnet to automatically give my login and password? 
There was something about using chat for that, in combination with
pppd.  I have an example in a script I have used in DOS with chat and user 
and passwd (?) and a few other things all on one line with epppd.

>> Can I telnet over a plip connection?
>
> Yes, you can telnet over any TCP/IP connection.  Ethernet,
> ppp, plip, whatever.

That would be faster but my parallel port tends to be busy. 
Nice to know next time I am transferring from/to a DOS laptop.

>> Serial transfer is about 10K/sec,
>> ethernet 1-10MB/sec
>> parallel was in between (1/40 of ethernet = 250K, 8x serial = 80K?)
>
> I get the following:
> serial:     9K/sec  @115200
I was rounding. 
> ethernet: 700K/sec
That is 10MBit ethernet.  The 100MBit is ten times as fast in theory.

> plip:      38K/sec
I thought parallel had 8 wires instead of the serial 1 and should be 8 
times as fast.  8-bit transfer.  Maybe it is 7-bit.  Did you do an actual 
measurement?  I was just guessing at it.

>
>> and laptops don't have ethernet connections
>
> On the contrary, any laptop with a PCMCIA slot can take
> an ethernet card (which are quite cheap these days).

Many laptops don't have ethernet.  We don't have any that do.
Most of our laptop computers don't have PCMCIA.  They do have parallel 
ports.  The new ones probably don't have those.  I don't use a laptop 
computer enough to care about speed of transfer.  It would be fun to take 
one to a friend's linux computer and connect via serial or parallel cable 
if they were willing to set that up.


>> I presume if kermit works over serial and ethernet it
>> will also telnet/transfer over parallel connection.
>> As should zmodem?
>
> Do you remember when I talked about a TCP/IP network
> being like a road?  It doesn't matter whether the road
> is built of concrete (ethernet), tar (ppp) or gravel
> (plip).  Once the road is up and running, you can drive
> your kermit (or whatever) from one end of the road to
> the other.
>
>> I then tried to run X from the dumb terminal
>
> That won't work.  Just like you don't get X on tty1
> when you startx on tty1.

I remember now.  Alt-F5 to get back to X when you started in on vt1, or 
Alt-F4 in BL3 (last vt is 3).  A dumb terminal is just like a virtual 
terminal.

I don't know what happens if you telnet (ppp, serial) to a computer and 
try to run X because of my  monitor situation.  X appeared on the other 
computer to which I had telnetted because my TTL monitor was using up the 
motherboard video RAM needed for VGA graphics.

>
>> Would BL3 in 4MB be able to connect to a computer with
>> more RAM (and monitor turned off) and run programs in X?
>
> Yes.  BL3 was designed for that very purpose.
>
>> Or even with 3MB?
>
> No.  4mb is the bare minimum for an Xterminal.

I can try this if I comment out mdacon.  Then I should be able to see the 
X screen on the computer from which I am telnetting.

>
>> Still don't know how to telnet over a serial cable.
>> Steven, did you actually have this working with BL2 or 3?
>
> (sigh) Yes.  I have personally tested (more than once)
> every one of the configuration options in /root/netsetup.

You forgot to tell me NOT to leave the s1:agetty line in inittab 
uncommented.

>
> Cheers,
> Steven
>



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