If your list does not have an Attachments= line in its
headers, all attachments are allowed. The same is true if it has
Attachments= Yes.
It's unlikely the ability to post any type of attachment
is what you really need. You might not need the ability to post attachments at all.
Attachments= No disallows any but plain-text attachments.
This is the safest setting.
Attachments= No,Filter accepts messages with any type of attachment,
but filters out the attachment itself. There may be situations where
this is useful.
Attachments= <filter based on MIME Content Type>
MIME content types are visible only in the full headers of an email
message, and look something like this: Content-Type: TEXT/PLAIN; charset=US-ASCII Here are some tested filters to allow certain types of attachments:
use as many or few as you need.