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Kermit - Technical Support

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Most recent update: Mon Mar 14 11:48:54 2011


Kermit 95 C-Kermit MS-DOS Kermit Other Kermits How to get technical support Troubleshooting hints


All software has bugs. Every time a new version of Kermit 95 is released, no matter how thoroughly tested, bug reports arrive after the fact. We document Kermit 95 bugs in several places:

Known bugs (most of them fixed, or with workarounds provided) at the time of the most recent release (HTML).

Bugs discovered or reported since the most recent release, often with workarounds (plain text).

Commonly reported problems are addressed here.

Kermit 95 was written over a period of years by members of the Kermit Project at Columbia University. It is essentially C-Kermit with Windows-specific code layered on top (notably the terminal emulator and the GUI features) and underneath (Windows file, device, and networking interfaces). Due to diminished revenues after the economic decline of 2000-2001, Jeffrey Altman, the author of the Windows-specific code (as well as of the security code – SSH, SSL/TLS, Kerberos, and SRP – and much else) was laid off and now has his own company, Secure Endpoints, Inc. All our Windows development expertise is now at that company, but no funds have been released for contracting for a new version. Therefore, on or before 30 June 2011, the source code for Kermit 95 (except for a few modules or sections of modules that are proprietary to other companies) will be released with the Open Source Revised 3-Clause BSD License.


C-Kermit 8.0.211 is the current version. C-Kermit 9.0 is in public testing. When it is ready, on or before 30 June 2011, it will be released with the Revised 3-Clause BSD License. For hints and tips, known problems, and tons of information about C-Kermit on different Unix platforms, CLICK HERE. For VMS CLICK HERE. For for installation instructions CLICK HERE for Unix, HERE for VMS. For a rather dated program logic manual (guide to the source code), CLICK HERE.


MS-DOS Kermit is still supported by the Kermit Project at Columbia University on a best-effort basis, but is no longer in active development. See the MS-DOS Kermit web page for further information.


Other Kermit programs (IBM mainframe, PDP-11, DECSYSTEM-10/20, PRIME, Honeywell, CP/M, and so on) are supported on a best-effort basis, but are no longer in active development (except sometimes).


The Kermit project offers technical support in the following ways.



Many people are not aware that there are hundreds of different Kermit programs on thousands of different hardware and software platforms, operating over all kinds of different connections. Not everybody is using the same Kermit software you are, on the same kind of computer, or over the same kind of connection. Before we can begin to help you, we need the following preliminary information:

  1. Is your question about Kermit software?

    1. If it is a question about email or some other application, even if you are accessing it through Kermit, then it probably is not a question about Kermit software itself. The Kermit help desk does not offer help with email programs or other non-Kermit applications, except to the extent that we can advise you choose the appropriate terminal emulation and help you set up the key mappings, if necessary. Otherwise, you will need to ask the owners, makers, or vendors of the non-Kermit application, or your organization's or ISP's local help desk, for help or instruction.

    2. A lot of third-party software packages include a Kermit file-transfer protocol implementation (usually not a very good one). If your software is not a Kermit software program from the Kermit Project at Columbia University, it is not our software and we can't help you with it. Kermit programs all have "Kermit" in their names, like MS-DOS Kermit, Kermit 95, C-Kermit, G-Kermit, Kermit-370, etc. If you are asking about the Kermit implementation in somebody else's software, you'll need to go to the maker or vendor of that software for help or instruction.

    3. If you have a problem transferring files with Kermit protocol between a Kermit Project program and a third-party product, we'll support our end of it. If the problem lies with the non-Columbia implementation, we'll do our best to provide a diagnosis or workaround, but we can not be expected to support or sanction improper or buggy Kermit protocol implementations in third-party products.

    If there is a problem with the interface between some other vendor's software and one of our Kermit programs, have the vendor of that software get in touch with us.

  2. Which Kermit program are you using? (What is its name? How does it identify itself when you start it?) The most commonly used Kermit programs Kermit 95, C-Kermit, are MS-DOS Kermit, and IBM Mainframe Kermit. (If your question concerns Kermit-32 on VMS, please note that Kermit-32 has not been supported since 1987; the supported Kermit software for VMS is C-Kermit).

      If you are using Kermit 95...
    Please take a look at the Kermit 95 Tutorial if you are having trouble getting started. Also the Kermit 95 Read Me document for orientation, file layout, etc. Then, before requesting assistance, please visit the Kermit 95 Frequently Asked Questions (FAQ) document; your issue might already be covered there.

    Did you start Kermit 95 from a Dialer entry? If so, does the same problem occur if you start Kermit 95 directly, without going through the Dialer?

      If you are using C-Kermit...
    Please take a look at the C-Kermit Tutorial if you are having trouble getting started. Before requesting assistance, please visit the C-Kermit FAQ and see if it helps.

    Also see the Kermit FAQ for issues that pertain all Kermit programs.

  3. What is the version number of the Kermit program? (Most Kermit programs have a "version" command; if not, the version number is announced when Kermit starts). If you are using an old version (see list of current versions), we will generally recommend that you install the current version and see if the problem still occurs. A list of current Kermit software versions can be found HERE. If you are using the current version of C-Kermit, we might recommend that you download the latest Development Build to see if the problem is already fixed (you might want to save time by doing this in advance).

  4. If it is Kermit 95 2.0 or later, are you using the GUI version or Console version? This information is especially important if your report concerns screen appearance, character sets, fonts, etc. At this point, everybody should be using the version 2.1.3 of K95 in its GUI form. There is no reason to use the Console version (which suffers from countless bugs and restrictions in Windows console application support) unless you really know what you are doing.

  5. Do you have the manual for your version of Kermit? Have you consulted it?

  6. If it is C-Kermit or G-Kermit, did you build it from source code, or are you using one of the prebuilt binaries? If you are using a prebuilt binary, which one? Are you sure it is the appropriate one for your computer? (To overcome such problems as library version mismatches, you might want to download and build from source.) If you built C-Kermit from source code, which makefile target did you use?

  7. On what kind of computer is your Kermit program running?

  8. What operating system and version is used on this computer? If your computer has Windows 95 or later but you are trying to use MS-DOS Kermit on it, please note that this combination is not supported; CLICK HERE for details.

  9. What kind of connection are you using (or are you trying to make)? Direct serial, dialup, Telnet, SSH, Rlogin, X.25, ...? If it is a modem connection:

    1. Which communication device are you using? Some operating systems have a selection of drivers for the same device, which are selected by using different names for the device; see, for example, the discussion of serial port names in HP-UX in the Unix C-Kermit "beware file".

      If you are using Kermit 95, you should be aware that it has two methods for accessing serial ports and modems; the traditional, built-in "DOS" method ("set port com1, set modem type usrobotics, ...") and the Windows-specific Control Panel interface ("set port tapi"). If one doesn't work, try the other. See the K95 FAQ for more about this.

    2. What kind of modem are you using? Is it internal or external? If you have a PC with an internal modem, is it a real modem or a "Winmodem"? If you think it might be a Winmodem, CLICK HERE.

    3. What kind of modem does Kermit think you are using? In other words, has Kermit been informed appropriately as to your modem type?

    4. What are the serial port communications parameters: speed, parity, flow control? In most Kermit programs, these are listed by the SHOW COMMUNICATIONS command.

    5. What kind of modem is on the other end? What is the remote modem connected to? – A serial port on the computer, a terminal server?

    6. What other communications equipment is involved? – An X.25 PAD? A 3270 protocol converter? A terminal server? An intermediate computer? etc etc...

      A serial connection (direct or dialup) must have an effective form of flow control at every junction between computer (or terminal server, etc) and modem. This means that each pair of devices that are connected must be using the same kind of flow control, usually either RTS/CTS (hardware) or Xon/Xoff (software). If this is not true, there can be any amount of data loss or corruption on the connection.

    7. If your complaint is that you see garbage when the connection is made... please describe the garbage: is it 100% garbage? Or is some of the text recognizable?

      • If approximately 50% of the characters are wrong, you probably need to tell Kermit to "set parity even" (or other parity choice)

      • If all of the characters are wrong, there is almost certainly a speed mismatch between (a) Kermit and your modem, or (b) the answering modem's serial port and the serial port of the computer or device it is connected to.

    8. How did you make the connection? – Did you use Kermit's built-in DIAL command? If not, please try it ("help dial" for more information). The DIAL command automatically does what it can to synchronize serial-port speed, flow control, and other critical parameters between your computer and the dialing modem.

    If it is a direct serial connection:

    1. Are you sure you have the appropriate kind of cable (e.g. null-modem instead of modem)? CLICK HERE for more information about cables.

    2. Have you correctly identified the communication port to Kermit (e.g. COM1 or COM2 or a TAPI device name in K95; /dev/ttyS0 or somesuch in Linux/Unix, etc)? (SET PORT or SET LINE).

    3. Is the speed ("baud") the same on both ends? For example, if the speed is 9600 bps ("baud") on the far end, then Kermit's speed must also be set to 9600 (SET SPEED). A typical symptom of a speed mismatch is that you see characters on your screen but they are total nonsense.

    4. If the computer on the far end uses "parity", you have to set Kermit's parity to match: SET PARITY EVEN, ODD, or MARK. A typical symptom of a parity mismatch is that some characters are intelligible, some are not.

    5. If the terminal screen is completely frozen, you might have a flow-control deadlock, often caused by an incorrectly or incompletely wired cable or by transmission noise. Tell Kermit to SET FLOW NONE, and if that unsticks the screen, then you can come back later and fix the real problem.

  10. What kind of computer or device or service is on the other end of the connection?

    Is the device, host, or service text based? Is it a PPP server? Do you have to log in to it? Do you get a login prompt? Do you get a menu? Are you immediately connected to a Kermit server?

  11. What operating system and version does that computer use?

  12. If you are reporting a file-transfer problem: what Kermit program and version is on the other computer? Does the transfer fail at the very beginning (constant retrying of the first packet), or partway through? Does it happen the same way every time? NOTE: Most current releases of Kermit software do not support transfer of files larger than 2GB; forthcoming releases will do so on most modern Unix-based platforms.

  13. If you are reporting a terminal emulation problem: What kind terminal is your local Kermit program emulating, and what kind of terminal does the host computer think you have? If you are using C-Kermit, see the C-Kermit FAQ. If you are having problems with F keys, Arrow keys, the Numeric keypad, or the Backspace key, consult the appropriate items in the Kermit FAQ:

  14. What is the exact nature of the problem?

    • Failure to start at all?
    • Is it a failure to make a connection?
    • A failure to transfer files?
    • A problem with terminal emulation?
    • A problem in another area such as scripting?
    • Exactly what happens, compared to what you think should happen?
    • Is this something that has always happened, or something that used to work right and then suddenly stopped working? In the latter case, can you think of something that changed around the time the problem first appeared?

  15. What commands did you give? Is the problem reproducible?

If you are using email to follow up on a previous or ongoing matter, please include relevant portions of previous correspondence. If you want to send Kermit scripts for us to look at as attachments or enclosures, please give them a name that ends with .txt, not (say) .ini or .scr or .ksc. Virus scanners will remove them. Anyway, since Kermit scripts and logs are plain text, you can just include them directly in your message, there is no need to structure them as attachments.

Data communication is rarely as simple as we'd like it to be. From the very basic set of questions above, you can see that there are at least three, and perhaps as many as eight (or more) completely separate hardware and software components to your connection, all of which must be configured to interoperate with each other and to pass the desired data through.

This is why communications software can be harder to use than self-contained applications that stay inside your computer, where (hopefully) all quantities are known. Also note that when you are using Kermit to make a serial connection, you are performing the job of a network specialist – making a connection that did not exist before, probably using a variety of equipment and software from different makers. Network specialists need years of training before they can do this – don't expect it to be effortless, although sometimes it might be. Every case is different. (Network connections are usually easier, because network specialists have already set up the network for you.)

Kermit manuals are generally 400-700 pages long. A great many of these pages are devoted to the many and varied communication methods, and what that can go wrong on each one, and methods for diagnosis and repair of problems. Please use the manuals. If you have suggestions for making them better, send them to us.

Thank you for helping us to serve you better!

Frank da Cruz
The Kermit Project
Columbia University
New York City

Kermit Tech Support / Columbia University / / Last update: 14 March 2011