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Frequently Asked Questions

What's this?

Most recent update: Wed Feb 15 11:40:23 2006



This document replaces the original Kermit FAQ, which can still be accessed HERE. The original FAQ is organized chronologically; this new one is organized by topic and contains mainly just links to other pages. For example:

This document pertains to Kermit "as a whole". Major Kermit programs, in turn, have their own specific FAQs, e.g.:

[ Contents ] [ Kermit Home ]

Which Kermit Program(s) Do I Need?

Kermit software can be used for many purposes. If all you want is a terminal emulator for serial or network connections for your Windows or DOS PC, use Kermit 95 or MS-DOS Kermit, as appropriate. If you want to transfer files, you'll need two Kermit programs, one for each end of the connection. For example, if you want to make a connection from Windows XP to a Sun Solaris server, you'll need Kermit 95 for Windows and C-Kermit for Solaris.

Here's a quick overview:

UNIX, (Open)VMS, QNX, OS-9, Plan 9, AOS/VS, VOS
(Full-featured network and serial communications and scripting)

UNIX only
(File transfer only).

Windows 95, 98, Millenium Edition, NT, 2000, XP
Kermit 95
(Full-featured network and serial communications and scripting)

Kermit 95
(Full-featured network and serial communications and scripting)

MS-DOS, PC-DOS, DR-DOS, or Windows 3.11 or earlier
MS-DOS Kermit
(Full-featured network and serial communications and scripting)
Note:MS-DOS Kermit is not supported on Windows 95/98/ME/NT/2000/XP or OS/2, not even in a "DOS window".

IBM mainframes with VM/CMS, MVS/TSO, or MUSIC
IBM Mainframe Kermit


[ Contents ] [ Kermit Home ]

Where To Find Things

The Kermit Project started in 1981 and has been developing and accumulating software ever since, so there is a lot of stuff here. Originally it was available only by mail order on magnetic tape. When the ARPANET (later Internet) became more widely available, the master tape directories were made available for public FTP access. Eventually the demand for tapes dwindled away but we still have thousands of files organized "by tape", with naming conventions designed for flat and unstructured tape archives with short filenames. This makes FTP access somewhat difficult:


But that's OK since almost all access nowadays is through our website:


which provides quick access to our most popular items, such as:

But there are lots more, some of them dating back a decade or two. A concise (but long) list is here:


The list is sorted by the contents of the "Machine" column. "Prefix" refers to the filename prefix, "Tape" refers to the subdirectory of the Kermit FTP site. Here's an example:

  Prefix,                 Operating  Program   Program  Released
   Tape  Machine          System     Language  Version  yy/mm/dd  Contributor
  MU  D  Honeywell        MULTICS    PL/I         2.0h  84/09/20  Oakland U

Kermit 2.0h for Honeywell MULTICS, written in PL/I at Oakland University, released 20 September 1984, is in the kermit/d directory of the FTP site, with filename prefix "mu". Even though the Prefix and Tape designators are listed in uppercase, you must enter them in lowercase because the FTP (and Web) site is now Unix-based (originally it was on a DECSYSTEM-20 where filenames were case-independent but shown in upper case). So to get the MULTICS version of Kermit, you would use FTP something like this:

  $ mkdir multics                (create a directory and cd to it)
  $ cd multics
  $ ftp kermit.columbia.edu      (make the FTP connection)
  Name: anonymous                (log in as user 'anonymous')
  Password: myuserid@host.domain (supply your actual email address)
  ftp> cd kermit/d               (change directory to kermit/d)
  ftp> prompt                    (allow multiple files)
  ftp> ascii                     (transfer in ascii text mode)
  ftp> mget mu*                  (get all files whose names start with mu)
  ftp> bye                       (log off the FTP server)

For detailed instructions about FTP, CLICK HERE. To find out how to use Kermit itself, instead of FTP, to download from the Kermit site, CLICK HERE.

[ Contents ] [ Kermit Home ]

Common Misconceptions

Click on any of the following to read about it:

Others discussed here:

Don't Use Telnet, Use SSH!

On the newsgroups, whenever anyone asks a question that contains the word "telnet" (or "ftp"), the answer comes back within milliseconds: Don't use Telnet, use SSH! (or Don't use FTP, use SCP!) (or SFTP). This confuses two orthogonal concepts:

  1. Virtual Terminal (or File Transfer) protocols
  2. Security

There's nothing wrong with Telnet. In fact it's far superior to SSH as a virtual terminal protocol in terms of features and extensibility, not to mention platform neutrality. Of course clear-text Telnet is insecure because passwords travel in the clear across the network, but apparently few people realize that secure Telnet clients and servers have been available for years, and these are more secure than SSH for reasons explained HERE. (If you don't bother to follow the link, the short version is manageability, especially regarding recovery from compromised keys.) Increasingly, Internet standard security methods such as Kerberos and SSL/TLS are included in standard distributions of Unix (Linux, FreeBSD, OpenBSD, AIX, Solaris, HP-UX, ...), VMS, and other operating systems, supported in their Telnet and/or FTP servers and/or clients. And of course they are also supported by C-Kermit for Unix and VMS and by Kermit 95 for Windows (which also supports SSH v1/v2).

Similarly for FTP. SCP and SFTP are not only not platform neutral, they're diversity-hostile. They transfer files only in binary mode, which mangles text files across different platforms, to the same degree the platforms' text-file record formats and character sets differ. An extreme example would be a Variable-Block format EBCDIC text file on an IBM mainframe, binary transfer of which to Unix would do you little good indeed. FTP was designed with diversity in mind and secure versions are available.

Of course SSH has its place, but you should use it with your eyes open, especially from Windows (where key files are easily stolen). SSH is best suited for trivial cross-realm applications. For example, if you have guest IDs at other sites for building an application on different platforms. Formerly Telnet and FTP would be used for this but now these paths tend to be blocked. However, even if the remote site has Kerberos service or X.509 certificates, it would be unnecessarily time-consuming to set up the cross-realm authentication and/or ticket forwarding for little one-shot jobs like this. In this case, SSH with manual password authentication is fine.

But for more serious work, especially within large organizations such as universities, corporations, laboratories, and government agencies, where your whole online identity is at stake, a manageable centralized security architecture is essential.

[ Contents ] [ Kermit Home ] [ Kermit Security Reference ] [ The Kermit FTP Client ]


Kermit software licensing is explained HERE.

Licensing is a hot and contentious topic. The public increasingly expects software to be "free" (with various and differing interpretations of the word free), and yet software is the product of human labor, which ultimately must be paid for, particularly if it takes place full-time over a span of decades.

The Kermit Project is composed of a core of full-time computing professionals at Columbia University in New York City, plus volunteers at other locations. Although the University paid for the Kermit Project initially, funding was withdrawn in the mid-1980s, and since then we have been funded solely by the revenue we can generate through sales of books, software licenses, and support contracts.

With the exception of Kermit 95, which must be bought and paid for, Kermit software is free in the sense that you can get it for free -- including the source code -- by downloading it; you can use it for free (even within a commercial setting); and you can even get e-mail technical support for free (within reason).

However, this freedom does not extend to redistribution of the software in a commercial setting: furnishing it to customers or clients, bundling it with products, and so on. If you want to gain commercial advantage from our work, you must help to support our work by licensing the software for redistribution. The specific terms and conditions depend on the product and other factors, and are given on our licensing page. This policy is fair and makes perfect sense: if your business depends on our products, it is in your best interest to keep our product alive and strong.

A recent exception to this policy allows inclusion of C-Kermit with free (in the Open Source sense) operating-system distributions such as Linux and FreeBSD. See the C-Kermit License for details.

Another exception is G-Kermit, which is released under the GNU Public License.

[ Contents ] [ Kermit Home ]

General Questions

[ Contents ] [ Kermit Home ]

File Transfer

[ Contents ] [ Kermit Home ]

Terminal Emulation

[ Contents ] [ Kermit Home ]

Modems and Dialing

Perhaps the most common problem in this area is that people "set modem type hayes" or (older syntax) "set modem hayes", thinking this means "any modem that uses AT commands." No, Kermit's "hayes" modem type is the actual Hayes 1200 or 2400 SmartModem from long ago. These modems did not support error detection and correction, compression, flow control, or speed buffering. If you use Kermit's "set modem type" command as documented to pick the kind of modem you are actually dialing or (in most cases) just go with the default, which in recent Kermit versions is "generic-high-speed", dialing should work. If you have trouble, use "set dial display on" to watch the dialog between Kermit and the modem, and then consult your modem manual to see what's wrong.

[ Contents ] [ Kermit Home ]

Kermit 95

Runs on: Windows 95, Windows 98, Windows ME, Windows NT, Windows 2000, Windows XP, OS/2
Current version: 2.1
Released: 25 November 2002
FAQ: See the
Kermit 95 FAQ

[ Contents ] [ Kermit 95 ] [ Kermit Home ]


Runs on: UNIX, VMS, VOS, AOS/VS, QNX, OS-9, Plan 9, BeOS, Commodore Amiga
Current version: 8.0.206
Released: 24 October 2002
FAQ: See the
C-Kermit FAQ, plus the following.

NOTE: "UNIX" is a general term covering the many operating systems that descended from the original Bell Labs UNIX operating system. Examples include: Linux, FreeBSD, NetBSD, OpenBSD, Solaris, SunOS, AIX, HP-UX, IRIX, OPENSTEP, NeXTSTEP, System V, Tru64, OSF/1, DG/UX, Unixware, Xenix, OpenServer, BSDI/OS, Ultrix, Digital UNIX, SINIX, and many more (for a longer list, CLICK HERE).

[ Contents ] [ C-Kermit ] [ Kermit Home ]

MS-DOS Kermit

Runs on: Windows 3.x and earlier, MS-DOS, PC-DOS, DR-DOS, etc.
Current version: 3.15
Released: 15 Sep 1997

[ Contents ] [ MS-DOS Kermit ] [ Kermit Home ]

IBM Mainframe Related

[ Contents ] [ IBM Mainframe Kermit ] [ Kermit Home ]

The Kermit FAQ / The Kermit Project / Columbia University / kermit@columbia.edu