converting TNEF attachments?

[Gunnar Wrobel]

Nik777 <kolab at babel.homelinux.net> writes:

> Hi All,
>
> I have switched our email from an old Sendmail/imapd machine to a new 
> Kolab machine. All users are extremely complimentary about the 
> performance and robustness of the new system.
>
> However, I had tnefclean installed and working on the old server, and am 
> now looking for a way to implement the same on Kolab. With tnefclean, 
> those nasty WINMAIL.DAT attachments were converted into regular MIME 
> attachments, so that non-Outlook users (eg Thunderbird) could see and 
> read them.
>
> I see that Kolab's amavisd does load Convert::TNEF at startup. However, 
> it seems this is just used so that such attachments are scanned, rather 
> than converting them to MIME.
>
> The tnefclean program is a perl script which can be run as a filter, 
> copying its modified output to stdout. So in my Sendmail configuration, 
> I simply added a rule to procmailrc which filtered all mail through 
> tnefclean.pl.
>
> So my question is: how can I easily get Kolab's postfix server to filter 
> all mail through tnefclean? I'm hoping that one of postfix's filter 
> options will be appropriate, although all documentation I've read on 
> that so far seems to indicate that I need to "reinject" filtered emails 
> back into a separate instance of postfix. Since tnefclean is simply 
> modifying a streamed email, I'm not sure if this would work?

The current postfix configuration already uses this reinjection scheme
several times. So I believe there is no need for you to add another
such reinjection loop but rather hook your tnef script into an already
existing loop.

My suggestion would be to try to do that with the
"kolabmailboxfilter". This script is responsible for delivering to the
users mailboxes. You should be able to wrap this script with a small
wrapper that pipes the input into your tnef script prior to piping it
into the kolabmailboxfilter scipt. You need to ensure that
kolabmailboxfilter receives all the arguments it need though.

I did not test this and it is just a rough idea. But maybe it works. 

Cheers,

Gunnar

>
> I notice that there is procmail in my Kolab installation, but it seems 
> unused, and the only articles I found regarding enabling it stated I had 
> to put entries into my config files for all Kolab users. This is not 
> viable with our installation, as new users are created regularly by 
> non-technical office admin staff using the Kolab web interface. They are 
> not in a position to modify Kolab config files.
>
> It also seems that Sieve is not capable of calling an external filter 
> program? Am I correct on this?
>
>
> Can anyone advise on how I should do this, or on where I should start 
> testing?
>
> Many thanks in advance for all suggestions.
>
> Cheers!
> Nik
>
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E-mail : p at rdus.de                                 Dr. Gunnar Wrobel
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