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Free Host-Based TN3270 Solution? 28

Posted by Cliff from the digging-oneself-out-of-proprietary-software-hell dept.
photozz asks: "Our company has got itself into a bind. We need to standardize on a TN3270 emulator for the Wintel boxes in our environment (primarily Win2K) The Linux/Unix guys are OK already )of course), unfortunately, the budget has run out. Our preferred solution would be something host based, but a client side solution would work. Sun has some Java stuff, but I figured if anyone would have a range of solutions, it would be this community. Anyone have ideas? If it matters, we are looking at 1000-2000 clients."
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Free Host-Based TN3270 Solution? More

Free Host-Based TN3270 Solution?

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  • free stuff (Score:3, Informative)

    by Pauly ( 382 ) on Tuesday May 07, 2002 @09:22PM (#3481768)
    Why not set up a shell server that your users log into and then from there use any of the ample, able 3270 emulators to then connect to the ultimate destination(s)? All you should need for 2000 clients is any reasonably modern FreeBSD/Linux box with a fat LAN connection.

    • I don't see how this would work (?). tn3270 is a completely different environment (although still text-based for the most part). The client he's talking about is probably x3270, which is an X11 program; "regular" terminal emulators (like windows telnet, putty ssh, mindterm, etc), cannot do what tn3270 needs.

      You could combine these ideas: get a bunch of old boxen, put Linux on them, get them a FAST network connection (network will probably be the bottleneck here), create accounts for your 1000 users (or be creative and use pam_ldap, pam_samba, whatever is appropriate for your environment) and have them run an X server on their PCs. You might try cygwin's compile of XFree86. It's actually decent, although it's not rootless. I don't know what the prices are for eXceed or other commercial X servers, but XFree86 under cygwin is OK and the price is right.

      If you go with cygwin, you can cut the Linux boxen out of picture (definitely a good idea). I don't believe x3270 comes with cygwin, but it should compile OK (I haven't had any problems compiling fairly complex X stuff under cygwin). Installing cygwin company-wide shouldn't be too much of an issue as the install just copies some files and runs one shell script to create /etc/passwd after installation.

      But yeah, if you're looking for a free native NT client, I haven't found one. All the places I've worked at that have these mainframes (a total of two) actually paid for their clients. I don't know if there will ever be one, since the communities of old mainframes and windows shareware are worlds apart.

      • Re:free stuff (Score:1, Informative)

        by Anonymous Coward
        It is possible to run a text-based tn3270
        client over a telnet session. It's odd,
        it's slightly kludgy.
        My university does this,
        because not everyone's got tn3270 clients,
        and the student records software is tn3270.

      • Re:free stuff (Score:5, Informative)

        by ddstreet ( 49825 ) <ddstreet.ieee@org> on Wednesday May 08, 2002 @12:41AM (#3482602) Homepage
        The client he's talking about is probably x3270

        x3270 is the X version; the 3270 package [geocities.com] comes with c3270 also which is the curses version. That's the one to use. It works fine with a default cygwin install [cygwin.com]. I've already tried it. However not everyone may want to install cygwin, but c3270 runs fine over a telnet/ssh into a UNIX box (from Windoze or any other system), so it's easy to simply set up a single (or several) UNIX boxes for the 10,000 people to telnet/ssh into and run c3270.

        The only caveat is the 3270 protocol sucks, and there are many "control" characters like Ctrl-C, Ctrl-X, etc that does "clear", and "reset", etc. It's in the 3270 man pages [geocities.com].

  • Well, if a Linux/Unix solution will work for the Linux heads, why not install Cygwin and get an X server up and running ( I don't know if it does headless or not ). Connect up a Linux box, and use the 3270 emulator off the remote machine. Not ideal, but it will work.

    No it isn't easy, but it is nearly free. Extra Linux servers might be costly, but the licensing is free.

  • you need a 3270 client. can't you use cygwin?
  • I'm sure there must be many solutions that won't cost anything, or at least very little. If you really want to do X-windows on the PC, I highly recommend XWin32 [starnet.com] from Starnet. If you're interested in free or shareware TN3270 clients, then I suggest you start downloading any of these [google.com].
  • I had to access a TN3270 server a while back. Luckily there is a great freeware client for the Mac. [brown.edu]

    Someone else mentioned the clients on Tucows. I checked each of them, and they are all shareware. They might be willing to allow a site licence if you drew a nice check, but it sounds like a free client would be better.

    I could not dig up a freeware client for Windows that will run across the board (3.x up to XP and ME). In fact, I had trouble digging up a free client at all.

    About the only thing I found was on a search of SourceForge. Freehost3270 [sourceforge.net] is apparently in alpha testing right now, but it is probably worth a look. You might even be able to help out. It also has the benifit of being on the server side and not the client side.
  • tn5250 is available for Windows, and free. Does it really have to be a 3270? You should be able to use a 5250 instead of a 3270 without your users noticing too much. AS400s will talk to a 5250 just as easily as a 3270, and I don't think the keyboard layout is even different. Try it out.
    http://tn5250.sourceforge.net/

    For those who haven't had the pleasure, 3270 and 5250 terminals are field based devices, not character based devices. You can't just use a VT100 and send different escape sequences.

    I used linux boxes to provide inexpensive 5250s to our users, but that was before tn5250 was ported to Windows.

    Your Windows users could run a PC x-server connected to a linux box running the x3270 emulator, but that sounds irritating.

    I don't miss the green screens, but the AS400 itself was a rock. I never saw unscheduled downtime, but that's not unusual. I was only there for a few years.
    • Maybe he's trying to go to a zSeries machine in which case it MUST be 3270. 5250 is for the AS/400, 3270 is for the mainframe. You can't just change between the two and expect it to work!
    • If you use a 5250 emulator check out tn5250j (http://tn5250j.sf.net) it has better keybinding support and is written in java so it runs anywhere.

    • Right, TN5250 emulation is very similar to TN3270 - both of which are *extremely* different from regular telnet, because you are emulating a EBCDIC "half-smart" terminal rather than an ASCII dumb terminal.

      You can readily configure any good quality TN3270 transport to be a TN5250 emulator - just prepend an extra escape to some function keys, basically. As long as you have key remapping ability (something all decent emulators have) it's trivial.

      I use the (relatively cheap, but not free) QWS TN3270 emulator from Jolly Giant Software in Canada to do this - it is far better quality than anything from Attachmate, Wall, etc. and costs much less.

      Most proprietary 3270 and 5250 clients share resources, and consequently anything that goes wrong in one session impacts all other sessions - drop a few bits talking to mainframe A, the session bluescreens due to the latest windows security patch treading on some part of the IP stack, and when you kill the offending session you lose your other six sessions to mainframes B through G.

      QWS 3270 [jollygiant.com], on the other hand, is implemented as a single session per image - you could crash one (something I've never managed to do accidentally, despite having dozens of simultaneous sessions) and it wouldn't do anything to the others. This is obviously a very big deal!

      OK, enough shilling for Canucks, the TN3270 and TN5250 protocols are documented in the eponymous RFCs. The differences are pretty trivial, and creating one from the other should be easy in the Open Source world.

      --Charlie
  • Try http://www.mochasoft.dk/ . At 250 US$ for a unlimited company license, it is as free. Hope you can afford that. A very good product if i ever used one. Much better then that crap that IBM gives us called Client Access. Talk about bloated. With friends like them who needs enemies. :)

    /Pedro
  • I am currently running it on Linux and Apache. Clients access a Java based web site, and that is it. It works great, you won't be sorry.
  • Try the QWS emulator. Here's a link to an older version:

    http://www.state.ky.us/binaries/windows/qws3270. zi p

    Don't give up hope, though. It's ridiculous to switch OS's just so that you can run an emulator.
  • A search on Google [google.com] comes up with QWS3270 [ncn.com], also available here [mcgill.ca]. A 90K freeware TN3270 emulator.

  • Set up a strong linux or OpenBSD server with OpenSSH on it.

    Configure OpenSSH to allow passwordless access using nice big (e.g. 1536) keys.

    Configure a restricted account so that it can do absolutely nothing but run the curses-based version of TN3270.

    Define an SSH-command key so that anyone authenticating with that key gets automagically hurled into TN3270.

    Go get TeraTerm SSH by Teranisi and O'Callahan and load it on the client PC. This is freeware, albeit with a weird license.

    Modify TeraTerm's keymap to trigger the appropriate key sequences for your applications and users. This is highly idiosyncratic (speaking from experience).

    Script TeraTerm, using the TTMACRO tool, to connect to the linux server via SSH using the dedicated TN3270 command key.

    Voila, 100% free fully encrypted TN3270 on windows platforms!

    Caveats: 1) communication between the mainframe and the linux box is not encrypted, so put that part on a secure link. 2) You still have to pay for the intermediary linux box.

    --Charlie

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