Re: [Exim] filtering at SMTP DATA time?

On Fri, 5 Mar 2004, Jeremy C. Reed wrote:

| Can standard Exim do any filtering (like regular expressions) as SMTP DATA
| time?
|
| So a message can be rejected at end of DATA?

Yup.

| I read in Exim 4.30 Specification chapter 14 that exim filters is applied
| at the start of each delivery attempt. So I assume that could be long
| after the SMTP QUIT.

Ah - that's different - the "message filter" runs after acceptance. The
DATA ACL is what you want.


| Could this be done with acl_smtp_data policy control using "condition" and
| "match"?

Yup

| I read that add-on exiscan-acl adds a "regex facility". Is that the
| recommended (or only) way to do this before server sends acknowledgement
| of DATA?

The exiscan regex sees the entire message body. Without exiscan, you only
see the first N bytes (whatever you set in $message_body_visible).

That said, the main win with exiscan is the ability to call SpamAssassin
and/or an AV scanner - all during the dialog.

|
| I am hoping to learn how to do this without any add-on.
|

Any particular reason ? If you want to do your content scanning during
the dialog (which IMHO is *the* time to do it nowadays) then exiscan is
your friend.

Here, it helps us repulse about a million messages / week. We're happy;
not sure if the spammers are ;-))

--
Chris Edwards, Glasgow University Computing Service