|Editors:||Ted Holt||Managing Editor:||Mari Barrett|
|Howard Arner||Technical Editor:||David Morris|
Volume 1, Number 15 sponsored by:
Profound Logic Software, Inc.
We recently migrated from an OS/400 CISC box to a RISC box. Since then, I have noticed a difference in the spool file that logs FTP transactions. The message says "227 Entering Passive Mode". What is passive mode? Previously we would see the name of the file and member being transferred.
For an FTP transfer to take place, the client and server machines must handle two requests. By "request," I mean that one machine sends a message to the other, which must acknowledge the message. There are two FTP modes, which means there are two ways that FTP handles communication between the client and the server to begin a data transfer. The older mode, called active or normal mode, doesn't work well through a firewall. Under active mode, the client initiates one request and the server initiates the second request. The firewall sees the server-initiated second request as an attack and turns it away. In passive mode, the client initiates both requests, which suits the firewall just fine. This is a very skimpy explanation; you can find a good thorough clarification of the mechanics of the two modes at http://www.slacksite.com/other/ftp.html.
The AS/400 transfers data in passive mode by default. However, I am guessing that this was not always the case. I base this presumption on the fact that the SENDPASV FTP client command is found in V4R3, but not in V3R2, a CISC release. If I am correct, that would explain why you're now seeing the 227 message, but did not see it before.
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Regarding your backspace key mapping answer in the October 31 issue of Midrange Guru, you shouldn't use Cursor Left for the mapping of the backspace key because, although it is non-destructive, it doesn't behave like a dumb terminal's backspace key.
If you use Cursor Left and you press the backspace key when the cursor is at the beginning of a field it will simply move to the left one space, and the cursor will now be positioned in a non-input area. This is not the proper behavior for the backspace key.
Pressing the backspace key when the cursor is at the beginning of the field should position the cursor in the last position of the previous field, either on the same line or on a line above the current field. If the current field is the first field on the screen, the cursor will move to last position of the last field on the screen. If there is only one field on the screen, the cursor will move to the last position of the same field.
The solution is to use Character Backspace, which does behave like a dumb terminal's non-destructive backspace key. It's unfortunate that IBM chose to use a destructive backspace as the default, but it is nice that they did provide an alternative that fully corrects the behavior.
-- Steve Houts
Here at IBM, we use Personal Communications for everything since we can connect to any of our systems including the AS/400. As for the Rule key, I mapped it to CTL HOME which to me closely mapped to my old 5251 terminal. (Yes, I had the first one installed in Canada.)
One thing to watch out for, if you are using Version 5.0 of Personal Communications and Version 1.1 of Windows 2000 there are some bugs relating to the TAB key causing the session to freeze. Basically if the Cursor is positioned below the first tab field on a screen and you hit the tab key it will freeze. This type of screen is not common, but it is used by our MKS change management software.
IBM is aware of it and hopefully will fix it.
Have a great day and keep up the great work. I enjoy receiving your tips.
-- Jim Townsend
I just wanted to offer a few additional thoughts on your section "Automatically Reply To Inquiry Messages" in the recent October 17 issue of Midrange Guru.
One of the problems I always experienced when I used the System Reply List is that you have to turn the job on to make it look to the list. To get around this, some shops make this a standard part of the job description. This opens up a whole different can of worms, now you are auto replying to messages as fast as the AS/400 can generate them without any human involvement! This might be a bad thing if for example, you put in an entry to auto-extend a file when it fills up (e.g. in a data entry application). What if it's a batch job stuck in a write loop?
There are some nice products on the market now that can help you monitor for very specific situations and take a more "intelligent" reply. For example, if you've already auto-replied to this "situation" twice in the last ten minutes, don't auto reply again. Instead, send somebody a pager message or run a command, etc.
Visual Message Center from Tango/04 is one such tool. MessengerPlus from Byteware is another.
Thanks for the recommendations, Joe.
If you have a tough problem, our gurus can probably help. Their mailboxes are always open.
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