Re: Telnet zmodem - Protocols

This is a discussion on Re: Telnet zmodem - Protocols ; In article , marty wrote: : Using: C-Kermit 8.0.209, 17 Mar 2003, for Linux(RH 8.0) : : I have an account that allows me to connect via telnet to a SunOS 5.7 : server. Login presents me with the user ...

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Thread: Re: Telnet zmodem

  1. Re: Telnet zmodem

    In article ,
    marty wrote:
    : Using: C-Kermit 8.0.209, 17 Mar 2003, for Linux(RH 8.0)
    :
    : I have an account that allows me to connect via telnet to a SunOS 5.7
    : server. Login presents me with the user menu, one of the choices is to my
    : 'Personal files' section. Upload/Download features are via xmodem or
    : zmodem. In the past on the windows side, I've used Hilgreave's
    : HyperTerminal to do uploading/downloading to my 'Personal files' section.
    :
    : But know I'm using RedHat... & C-Kermit 8.0.209, 17 Mar 2003, for Linux. As
    : powerful as C-Kermit is I figure it should allow me to do the same as I did
    : on the windows side but...
    :
    : From a C-Kermit prompt I telnet to and log onto the server. The procedure
    : for downloading via a telnet connection is to choose the download option
    : and name the file one wishes to download. Chose xmodem or zmodem
    : (C-Kermit: set protocol zmodem) and the process begins...
    :
    "set protocol zmodem" invokes an external protocol, whatever Red Hat happens
    to have installed as "rz" and "sz".

    : ================================
    : Receiving: pine-error_addressbooks.png
    : Retry 0: Bad CRC
    : ...
    : Bytes received: 0/ 30846 BPS:0 ETA 00:00 Retry 0: Bad CRC
    : ...
    : Retry 0: Bad CRC
    :
    : rz: pine-error_addressbooks.png removed.
    : ================================
    :
    : The process finishes with me being dumped back to the C-Kermit prompt.
    : Status: FAILURE
    :
    So "rz" failed.

    : Uploads are just as unsuccessful. I start with a login to a telnet session
    : from the C-Kermit prompt. Initiate an upload using zmodem (again C-Kermit
    : is 'set protocol zmodem', do a Ctrl\c back to C-Kermit prompt issue the
    : following...
    :
    : The file name shows in the list of files in my 'Personal file' on the host,
    : but of course the file is 0 KB.
    :
    : I've only been using linux for a year or so now and C-Kermit for a few days
    : so any help or suggestions would be much appreciated.
    :
    Some knowledge of serial communication is required. The C-Kermit book has
    chapters and chapters explaining all this. Very briefly:

    . We know the interface speed is right because you can see the
    remote text.

    . Probably the parity is right ("none") because the host would never
    pick Xmodem or Zmodem as protocols if non-none parity were being
    used.

    . Therefore the most likely cause of failure is inadequate flow
    control.

    You have to make sure an effective form of flow control is established
    between every pair of devices along the communication path, e.g. local
    computer to its modem, modem to modem, remote modem to remote serial
    port. See:

    http://www.columbia.edu/kermit/support.html#hints

    if you need to follow up.

    - Frank

  2. Re: Telnet zmodem

    Frank da Cruz wrote:

    > In article <0r9_a.319$jw4.275@nwrdny03.gnilink.net>,
    > marty wrote:
    > : Frank da Cruz wrote:
    > : > In article ,
    > : > marty wrote:
    > : > : Using: C-Kermit 8.0.209, 17 Mar 2003, for Linux(RH 8.0)
    > : > : ...
    > : > : From a C-Kermit prompt I telnet to and log onto the server. The
    > : > : procedure for downloading via a telnet connection is to choose the
    > : > : download option and name the file one wishes to download. Chose
    > : > : xmodem or zmodem (C-Kermit: set protocol zmodem) and the process
    > : > : begins...
    > : > :
    > : > "set protocol zmodem" invokes an external protocol, whatever Red Hat
    > : > happens to have installed as "rz" and "sz".


    (lrzsz) 0.12.20 I believe this was the last available 'free' version that
    is in the public domain?

    > :
    > : Yes I was aware of that fact, thanks.
    > :
    > Yes but I didn't know you were aware.
    >
    > : > : The process finishes with me being dumped back to the C-Kermit
    > : > : prompt. Status: FAILURE
    > : > :
    > : > So "rz" failed.
    > :
    > : Actually, I wrongly stated that status reported 'FAILURE'. In fact
    > : after all of these failed transfers, typing 'Status' at the C-Kermit
    > : prompt reports: 'SUCCESS'
    > :
    > Probably you gave some other command that succeeded after the failed
    > file transfer and before the STATUS command. From your posting, it's
    > clear that Kermit reported failure.
    >


    I think I now understand why C-Kermit reports status: SUCCESS ? After the
    xfer attempt, I reconnect to the host. The host message is reporting 'File
    transfer complete' although there was no transfer?

    > : > Some knowledge of serial communication is required. The C-Kermit book
    > : > has chapters and chapters explaining all this.
    > :
    > : Ok, so you would like me to buy your book! Maybe I will, but in the
    > : meantime your help is greatly appreciated.
    > :
    > My point is that it takes a lot of explaining, more than you'd expect me
    > to
    > type in the response to a newsgroup posting. That's why we wrote the
    > books. We definitely do not get rich from them.


    Ok, it was just an feeble attempt to inject a bit of my lame humor into this
    thread! From re-reading the C-Kermit man-pages I see that you are one of
    the main software developers of C-Kermit AS WELL AS author of the man, the
    manual, etc. Ouch! Please accept my apology.

    >
    > : > You have to make sure an effective form of flow control is established
    > : > between every pair of devices along the communication path, e.g. local
    > : > computer to its modem, modem to modem, remote modem to remote serial
    > : > port. See:
    > : >
    > : > http://www.columbia.edu/kermit/support.html#hints
    > :
    > : Thanks for the link but one minor detail I failed to mention. My
    > : connection to the remote host is via broadband and the Internet, no
    > : modem(s) involved. I've tried various flow-control settings for both
    > : 'tcpip' and 'remote' to no avail?
    > :
    > Then it's a Zmodem protocol failure, which is prone to happen over Telnet
    > connections due to Telnet NVT rules, which Kermit obeys but many Zmodem
    > implementations do not. Some of them might have a command-line option to
    > force them to adapt to Telnet connections. Kermit protocol would work a
    > lot better


    From what I have read, I am sure your are correct.

    -- you might want to mention this to whoever is in charge of
    > the other end.


    They don't care. This is a free account provided by my local library via a
    library cooperative (www.suffolk.lib.ny.us). Heck, the only Online support
    they provide is to windows and mac types! It took three or four eMails to
    tech support for them to come up with untried software suggestions,
    C-Kermit being one of two.

    Meanwhile, you'll have to look at the rz and sz programs
    > on your Linux system and see what command-line options are available and
    > tailor Kermit's SET PROTOCOL command accordingly.
    >
    > - Frank


    *Bottom line*

    User error was to blame for the C-Kermit/zmodem/sz/SEND error. Once I
    entered the FULL path name to the file I needed to upload all works
    perfectly. (I had assummed that because I was in the file directory I
    could type SEND filename... never assume)

    Downloading is still the issue of failure, but I will continue to
    experiment. The fact that I can now do file uploads via telnet/zmodem to
    the host is most helpful.

    Frank, thanks for your comments and your patience. It is much appreciated.
    I won't trouble you further.

    marty
    --
    All UNconstructive criticism will be filed in the appropriate receptacle.

  3. Re: Telnet zmodem

    In article <8Vs_a.8529$UB4.2245@nwrdny01.gnilink.net>,
    marty wrote:
    : ...
    : User error was to blame for the C-Kermit/zmodem/sz/SEND error. Once
    : I entered the FULL path name to the file I needed to upload all works
    : perfectly. (I had assummed that because I was in the file directory I
    : could type SEND filename... never assume)
    :
    There's nothing in Kermit that requires you to give a full path. The
    regular Omen rzsz doesn't require it either. It must be a quirk of
    lszrz.

    : Downloading is still the issue of failure, but I will continue to
    : experiment. The fact that I can now do file uploads via telnet/zmodem to
    : the host is most helpful.
    :
    The lszrz program is unaware that you have a Telnet connection and I don't
    know if it would behave any differently if it *did* know. You might want
    to try putting the Telnet connection into binary mode. Tell Kermit to:

    set telnet binary-mode requested (or maybe "required")

    before making the connection.

    - Frank

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