Chris Linfoot | A Base64 Decoder and C.DTF

Friday, 23. January 2004

A Base64 Decoder and C.DTF

This seems to be a not uncommon issue with Internet email received at Domino sites. A message turns up in a user's in-box apparently empty bar a single attachment named C.DTF.

This appears to be caused by certain multipart/mixed MIME messages addressed to users whose PAB documents say they prefer Notes Rich Text. The MIME to CD conversion at the server has for some reason been unable to convert the message properly and the entire MIME source is delivered as a single attachment usually named C.DTF. The solution is to have users' PAB documents say they prefer mail to be left in the sender's format, so MIME stays as MIME and is interpreted by the Notes MUA, which does a better job in the case of these multipart/mixed messages.

But what to do when you already have a C.DTF file and it has contents you wish to see?

Firstly - save the file to a folder and open it in Notepad (or any text editor). You will be able to see any text parts of the message right there.
You can select HTML parts and copy them to a new text document, then save as filename.htm and open in a browser.
If there are attachments you want, you can decode them straight from the C.DTF file using a suitable Base64 decoder.

A very useful (and free) decoder can be found here. This creates a shell extension in Windows, and a new item appears on the context menu when you right click on a file. Right click on C.DTF and select "Decode". And that's it.

You have now rescued the entire contents of the message without having to go back and beg the sender for a fresh copy.

Category: Software
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Comments :

1. Kompella01/10/2004 07:19:30

I am not able to decode my C.DTF file. After installing the decoder (from the link specified here), i do get a decode option in the right-click menu. On slecting that Decoder opens with the following message "C.DTF is not encoded".

The DTF file is supposed to contain a word document and an excel sheet.

2. Chris Linfoot01/10/2004 08:35:01

Open it in a text editor (Wordpad). What do the first few lines look like?

3. Tonny14/06/2007 07:49:48

I hope you can read the comment though 3 years passed...
I meet the same problem as you said here, and I also cannot decode the file as which comment 1 said. The first line of the dtf file is SYMANTEC TOUCHBASE DATABASE and some other ASCII codes. And I am certain that it contains at least one excel file.
I hope some further information from you.

Thanks a lot.

4. Chris Linfoot14/06/2007 08:43:50

Send me the C.DTF file and I'll take a look.

5. Kathy16/07/2008 23:14:00

What was your response to the guy above about the SYMANTEC TOUCHBASE DATABASE file he had. I ran a report on some old software we have at work and it produced a file with this heading at the top. I know it is from a database software but need to either print or get into access so that I can do something with it. thanks

6. Chris Linfoot17/07/2008 08:40:16

My response was comment 4 and he never sent the C.DTF, so I've never seen a sample. Send me yours if you like and I'll take a look.

7. Jammy23/09/2008 01:58:02

What about the Lotus Notes temp .DTF files, I have one that I need to open and so far no sucess, can I send it to you?, is is posible to decode files in the format: IDB38194.DTF?

8. Chris Linfoot23/09/2008 18:37:46

.DTF files are usually just raw MIME in text format. Rename the file to something.eml and try to open it in Outlook Express or Mozilla Thunderbird.

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