Personal Blog of Thomas Hampel - Creative Mythbusting in Development and Collaboration

Query results for : December 2011

Winmail.dat- 29 December 2011 - (1) Comments

Thomas Hampel
 29 December 2011

Every couple of years the same story...

Lotus Notes/Domino users reveive emails containing an attachment "winmail.dat" or "att00001.dat" which the Lotus Notes® client's is unable to open..
Examination of the document properties reveals that the message was sent as a Content-Type: application/ms-tnef; name="winmail.dat", which actually is a format only used by Microsoft® Exchange/Outlook

The problem itself is described in IBM Technote 1093342
http://www-01.ibm.com/support/docview.wss?rs=475&uid=swg21093342

but let me point out that this clearly is not problem caused by Lotus Domino, its the sender's fault which has configured its messaging system to send the email in a Microsoft specific TNEF format rather than using a common standard.
The Microsoft TNEF format is not at all a public standard like those documented within RFC's. Even Microsoft pointed out that the TNEF format isnt RFC compliant ( see Microsoft KBA #323483 )

According to IBM Technote 1093342 Domino administrators can enable a Notes.ini variable TNEFEnableConversion=1 on the server to improve situation, but this can only be a short term workaround because every time Microsoft decides to change the format of its TNEF file type, Domino wont be able to convert the data stored within. Furtheremore this file may contain specific content which Domino will never be able to convert properly such as voting buttons or custom forms.

A real solution is to fix the problem at the source, which is to remind the sender to turn off the sending of mails in TNEF format.
Microsoft published a knowledge base article http://support.microsoft.com/kb/241538 a few years ago which is suggests to turn off using the TNEF format either globally or per recipient.
Once again, this can only be done by the sender or actually the senders administrator, not by the recipient.

Please note:
If the sender is using Microsoft Exchange 2007, the format of "winmail.dat" has changed compared to earlier versions, so conversion will NOT work in some cases!!!
Since Microsoft is changing the format of the file winmail.dat whenever they want, the variable TNEFEnableConversion wont guarantuee to be working all the time - Domino server crashes will be the result.
This also is true for any upcomming changes in the file format.

To avoid misunderstandings :
  • TNEF Format is not based on common standards
  • Email clients other than MS Outlook can not handle TNEF, because TNEF may contain elements such as forms or voting buttons.
  • TNEF encoded raw binary independent of what is advertised by the receiving SMTP server. As documented in Microsoft KBA #323483, this technique is not RFC compliant.
  • Most Exchange Admins configure their servers correctly to NOT send TNEF encoded mails to recipients on the internet.
  • S/MIME signed emails will not be converted unless the Domino Administrator will force to break the digital signature by using the Notes.ini variable TNEFBreakSMIME=1

How to handle the problem:
  • Catch all mails with Content-Type: application/ms-tnef before they arrive the Domino server
    Return a message to the sender telling them that they should disable sending mails in TNEF format. Refer them to http://support.microsoft.com/KB/138053 for further instructions
  • Enable TNEFEnableConversion=1
    Why take this risk?? Simply because your users will be frustrated getting mails with "winmail.dat" attachments.
  • Do not use TNEFBreakSMIME=1
    Because security warnings where the client will get used to ignore are even worse

How many users a single Domino server can handle???- 5 December 2011 - (0) Comments

Thomas Hampel
 5 December 2011

In the past a lot of server.load tests have been done to "proof" that Domino can handle a certain amount of users.
As you can imagine, each simulation does not really reflect what a real user can do. Especially not the wide range of different actions.


So lets take a look into a production environment.... this environment is based on Domino 8.5.2 - 64Bit running on AIX.

Image:How many users a single Domino server can handle???

Showing a peak of 10040 users, within just one Domino partition. This statistic doesnt say if users were happy with the response time of the server at peak workload times, which of course is something that can be figured out. However the statistic shows that Domino can handle the workload when enough I/O capacity is available.

I'm not able to share more technical details but what I can say is that CPU and memory utilization were high, but not were reaching limits.

Creating PDF documents from within Notes/Domino- 3 December 2011 - (0) Comments

Thomas Hampel
 3 December 2011

How can PDF documents be rendered from within a Notes application?
Converting Notes documents into Adobe's PDF format can be a challanging task.
Many different software addon products for Lotus Notes/Domino are being sold to make this happen,
e.g. DominoPDF which is being used by some of my customers - but in fact you dont need anything else than a Java component inside of your application.

Simply by using the iText Library and a small piece of source code, you can add PDF conversion functions to your Domino application. Look at this video to see an example. The solution outlined here makes sense for embedding this functionality inside an application. For single computers instead, its most likely enough to look at FreePDF (english) a freeware PDF converter which installs itself as a printer device.

A really large Notes application which seems to exceed 100 TeraByte- 1 December 2011 - (0) Comments

Thomas Hampel
 1 December 2011

Another interesting observation in a Notes 8.5.3 client.

This Notes application, shows up in the Admin client with an incredible amount of disk space.

If I am calculating right 1,0*E^14 is 100 TeraByte in a single NSF file, which is located on my local computers disk.

Image:A really large Notes application which seems to exceed 100 TeraByte

Actually the physical disk size on operating system level shows a different value, of just 1.290.240 bytes

While the DB properties show 101 MByte...

Image:A really large Notes application which seems to exceed 100 TeraByte

I guess something is wrong here...
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