At 11:34 04-04-2008, Yves Goergen wrote:
>today my mail server (Exim) was almost killed by a series of
>message/partial messages to one of my clients' mailbox. From the
>inside, it looks like a 5 megabyte blob of base64 data, I haven't
>tried to decode it in raw. Since it is a partial message only, I
>guess one part of the whole can't be used to say anything about the
>entire message.


You need all the parts to reassemble the message and decode it.

>This is the first time in my life that I have seen the
>message/partial content-type. And the RFC number it appeared in was
>fairly low, so it must be an older standard. I'm wondering what MUA
>supports this, I have never seen such an option at the GUI surface.


MS Outlook and a few other MUAs support it. There's an option to
split a message into several parts.

>But what's a mail scanner/filter supposed to do with a partial
>message anyway? I mean, it can only reject it by policy or let it
>pass. There's nothing to tell about the actual message contents, is there?


You can still do a partial scan on the message but that won't be accurate.

At 11:39 04-04-2008, Theo Van Dinter wrote:
>IMO, I'd drop them by policy since I agree that I've never seen it used
>legitimately.


I've used it. It's a useful feature if you want to get around
message size limits to send attachments. It can also be handy when
there's poor connectivity.

If you have a strict email policy, you might as well drop this content type.

Regards,
-sm