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This month, we have information about Kerberos version 5.0, Postoffice and pop mail clients,, and some information about NAS classes. For those keeping track, there was no January Networking Nuggets.
Status of Kerberos at UIUC:

As most of you know, one of the reasons we support Kerberos on PC's and Mac's is U of I Direct. We have to be very careful about what we do to our Kerberos servers, to make sure that the currently deployed Kerberos clients (especially the many PC/TCP clients on PC's and NCSA Telnets with KClient plugin on Mac) do not break.

We have a few goals:

  1. Deploy a usable Kerberos telnet client that supports encryption to campus PC's and Macs. An ancillary goal is to deploy a "free" client that we can freely distribute, especially to students.
  2. Continue to support U of I Direct in the same manner as we do now - with a secure client from the desktop to the U of I Direct gateways.
  3. Move from our current MIT Kerberos server to a Distributed Computing Environment (DCE) security server, with an eye toward a future Distributed File System (DFS) deployment.
In order to do number 3, we need to replace our clients with Kerberos Version 5 clients. We were waiting for the December, 1996 release of MIT Kerberos 1.0, which promised to support PC's and Macintoshes with a Version 5 client. Because goal number 1 is so important, we have tested the included clients with an eye toward deployment. We have found that not enough effort has been put into the PC and Mac clients in MIT Kerberos 1.0. They are not ready for prime time yet. We do have hope that we will get an acceptable free client from MIT that can replace PC/TCP. We will continue to work on the clients to make them usable.

On the good side, the Windows clients that we do have from the MIT distribution are 32-bit windows applications and use the Microsoft TCP/IP stack. I know this will make many people who support OnNet simply for U of I Direct users very happy.

In summary, we need to make the clients usable, begin to distribute them, and then upgrade our servers (including the U of I Direct gateway machines) to the new code. This will take some time, and we appreciate your patience.

David Lemson
CCSO

The new load limiting sendmail on postoffice is helping out postoffice quite a bit but is causing a lot of heartburn for some misconfigured pop clients.

The problem occurs during the afternoon when the load on postoffice is very high and the incoming mail gets deferred to a spooling server for a few minutes until the load gets reasonable again.

We are in the process of evaluating an upgrade options for postoffice and have been forced to use load limiting to keep the machine from crashing and potentially losing mail.

A long time ago users were told to use postoffice.cso.uiuc.edu as their SMTP host for outgoing mail. This was before postoffice did nearly as much mail traffic as it does now.

Over two years ago users were instructed to start setting their SMTP host to be the same as the machine from which they pop. For example, if you pop from students.uiuc.edu you should set your smtp host to students.uiuc.edu, not postoffice. The same would go for staff.uiuc.edu and other pop servers as well.

If a user has a problem with *sending* mail with Eudora or netscape please make sure they do *not* have postoffice listed as their SMTP host.

Please note that the load-limiting sendmail does not mean that mail is being lost. In the case of servers attempting to transmit mail to postoffice, when a connection is refused, that mail is requeued and the remote server attempts to send the mail at regular intervals. The problem we are seeing only affects users whose pop mail clients are failing to send mail through postoffice. These users are being given an error message, and their mail program attempts to send the mail again on the next connection attempt.

NAS has completed a new on-the-web class registration interface! You can now register for NAS classes without cutting and pasting, or printing and sending through campus mail. You can access this interface directly via https://www-s1.cso.uiuc.edu/nas/classes/begin.cgi or through the link from the NAS classes form on the NAS home page at http://www.uiuc.edu/ph/www/admin-help.

Also, please note that in an attempt to help cover costs, you may be billed $50 if you fail to attend a NAS class you are scheduled for, or cancel less than 24 hours before a class. You are welcome to send someone in your place if you are unexpectedly prevented from attending. We do make every attempt to remind you of a class, but cannot be responsible if for some reason you do not receive a reminder.

If you have forgotten which classes you are registered for, or you submitted a registration form but do not recall getting a list of which classes you are registered for, you can send mail to nastrain@uiuc.edu to request this information.

Thanks!

CCSO NAS