Re: Re: Telnet and zmodem
  By: Michiel Broek to Rob Swindell on Tue Mar 07 2006 08:46 pm

 > Hi Rob,
 > 
 > Rob Swindell wrote to Michiel Broek:
 > RS>   Re: Telnet and zmodem
 > RS>   By: Michiel Broek to Rob Swindell on Mon Mar 06 2006 02:54 pm
 > RS>
 > RS>  > Hi Rob,
 > RS>  >
 > RS>  > it seems that the problems between syncterm and mbse are in the
 > RS> underlying
 > RS>  > network part. Mbse uses the telnet links as 8 bit link, syncterm
 > RS> escapes
 > RS>  > telnet control commands. I experimentyed with that too,
but they two
 > RS>  > programs still refuse to work together.
 > RS>
 > RS> When downloading via Zmodem, the upstream packets are all in ASCII, so I
 > RS> don't
 > RS> see how "escaping telnet control commands" in
SyncTerm would matter. Of
 > RS> course
 > RS> SyncTerm expects the Telnet IAC character (ASCII 255) to be
"escaped",
 > RS> that's
 > RS> how the Telnet protocol works. Is it this escaping of the IAC that you'r
 > RS> saying MBSE does *not* do?
 > 
 > The upstream seems not the problem, downstream. And yes I don't escape IAC
 > because on IP connections mbsebbs is run from inetd -> in.telnetd
 > So mbsebbs doesn't answer the incoming connections itself. In my opinion
 > in.telnetd handles the IAC escaping. The only thing mbsebbs does is put the
 > tty into raw mode using ioctl calls. And up/downloading data containing
 > character 255 is possible.

Yes, afaik, telnetd should be escaping the IACs for you. And if that's the
case, then can you expand on what "escaping" you were referring to that
SyncTerm does that MBSE does not?

 > RS>
 > RS>  > I did some more testing and made the following matrix:
 > RS>  >
 > RS>  >
 > RS>  >                 Mbsebbs       Synchronet    Concord      Mystic
 > RS>  >                 ------------- ------------- ------------
------------
 > RS>  > Dynacom-8 win   Ok            Ok            Error        Aborted
 > RS>  > mtelnet win     Ok            Ok            Ok           Ok
 > RS>  > Minicom Lnx     Ok            Ok            Ok           Ok (crc
 > RS> errors)
 > RS>  > Syncterm lnx    Error         Ok            Ok           Aborted
 > RS>  > TeraTerm win    Ok            Error         Ok           Error
 > RS>  >
 > RS>  > All were tested with a large download using normal zmodem.
 > RS>
 > RS> Of course Synchronet doesn't have any built-in x/y/zmodem transfer
 > RS> protocols so
 > RS> when you list "Synchronet" above, that's too vague
to be useful. Dependi
 > 
 > RS> on
 > RS> the BBS which you connected the sending Zmodem protocol driver could
 > RS> easily be
 > RS> FDSZ, CEXYZ, [l]sz, or SEXYZ.
 > 
 > I tried vert.synchro.net for this and selected Zmodem. Was that lsz?

vert.synchro.net uses SEXYZ (Win32). cvs.synchro.net uses lsz.

 > RS>  > To me it seems there are probably tiny differences which
break some
 > RS>  > combinations. We may better not discuss Mystic, it's possible that
 > RS> there is
 > RS>  > something wrong on the bbs side of that system, only
mtelnet did ok
 > RS> without
 > RS>  > errors, other programs finished ok with lots of crc
errors or aborted
 > RS> on too
 > RS>  > many crc errors.
 > RS>  >
 > RS>  > Do you have any ideas what the real problem may be between these
 > RS>  > incompatibilities?
 > RS>
 > RS> Not without more details. :-(
 > 
 > That's the problem, there still are no real details. But the new logging in
 > syncterm made a lot more clear already. I also have a cvs checkout here now
 > so I can make changes for myself if I need that.
 > 
 > My next plan is to look at the in.telnetd sources to see if something
 > therein does something I don't expect.

Let me know if you need any additional assistance.

                                                  digital man

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