To use the Spam
package to filter incoming mail, you must first set up fancy mail
splitting. See Fancy Mail
Splitting. The Spam package defines a special splitting
function that you can add to your fancy split variable (either
nnmail-split-fancy or
nnimap-split-fancy, depending on your mail back
end):
(: spam-split)
The
spam-split function scans incoming mail according to
your chosen spam back end(s), and sends messages identified as
spam to a spam group. By default, the spam group is a group named
‘spam’, but
you can change this by customizing spam-split-group.
Make sure the contents of spam-split-group are an
unqualified group name. For instance, in an nnimap
server ‘your-server’, the value
‘spam’ means
‘nnimap+your-server:spam’. The value
‘nnimap+server:spam’ is therefore
wrong—it gives the group ‘nnimap+your-server:nnimap+server:spam’.
spam-split does not modify the contents of
messages in any way.
Note
for IMAP users: if you use the
spam-check-bogofilter,
spam-check-ifile, and spam-check-stat
spam back ends, you should also set the variable
nnimap-split-download-body to t. These
spam back ends are most useful when they can “scan”
the full message body. By default, the nnimap back end only
retrieves the message headers;
nnimap-split-download-body tells it to retrieve the
message bodies as well. We don't set this by default because it
will slow IMAP down, and that is not an
appropriate decision to make on behalf of the user. See
Client-Side IMAP Splitting.
You have to specify one or more spam back ends for
spam-split to use, by setting the
spam-use-* variables. See Spam Back Ends.
Normally, spam-split simply uses all the spam back
ends you enabled in this way. However, you can tell
spam-split to use only some of them. Why this is
useful? Suppose you are using the
spam-use-regex-headers and
spam-use-blackholes spam back ends, and the
following split rule:
nnimap-split-fancy '(|
(any "ding" "ding")
(: spam-split)
;; default mailbox
"mail")
The problem is that you want all ding
messages to make it to the ding folder. But that will let obvious
spam (for example, spam detected by SpamAssassin, and
spam-use-regex-headers) through, when it's sent to
the ding list. On the other hand, some messages to the ding list
are from a mail server in the blackhole list, so the invocation
of spam-split can't be before the ding rule.
The solution is to let SpamAssassin headers supersede ding
rules, and perform the other spam-split rules
(including a second invocation of the regex-headers check) after
the ding rule. This is done by passing a parameter to
spam-split:
nnimap-split-fancy
'(|
;; spam detected by spam-use-regex-headers goes to ‘regex-spam’
(: spam-split "regex-spam" 'spam-use-regex-headers)
(any "ding" "ding")
;; all other spam detected by spam-split goes to spam-split-group
(: spam-split)
;; default mailbox
"mail")
This lets you invoke specific
spam-split checks depending on your particular
needs, and target the results of those checks to a particular
spam group. You don't have to throw all mail into all the spam
tests. Another reason why this is nice is that messages to
mailing lists you have rules for don't have to have
resource-intensive blackhole checks performed on them. You could
also specify different spam checks for your nnmail split vs. your
nnimap split. Go crazy.
You should set the spam-use-* variables for
whatever spam back ends you intend to use. The reason is that
when loading spam.el, some
conditional loading is done depending on what
spam-use-xyz variables you have set. See Spam Back Ends.