[Mimedefang] Spam to inactive accounts

Geoff Thornton gthornton at networks-group.com
Fri Oct 18 11:38:00 EDT 2002


Yes, the trick would to extract the active user information into a
accessdb/virtusertable/aliases format, and I suspect that many people are
doing just that.  I'm doing that to a limited degree already.  It's just
that's it's a _manual_ process that must be done on the end mail system and
the process differes depending on what type of end mail system is being
used.

I think that the suggestion was to create a portable and automatic method on
the MIMEDefang side to add similar functionality without relying on sendmail
or manually generating access / virtual user / alias lists. I'm sure the
many people already have an acceptable procedure in place for generating
these files... I don't.  I'm also lazy.  And I also like to program (small
programs) :-)  That's why I'm interested in an interface that will do all of
the work for me.

That way when a new user is added, I don't make any changes--the first email
send to the user will automatically add an entry for that email address.
Then when that user leaves, cached information about that user will
automatically expire and then user will automatically be switched from a
valid to an invalid recipient.  When mail eventually stops going to that
mailbox, that entry will automatically be deleted.

That seems like a pretty nice framework to me.


--Geoff Thornton

-----Original Message-----
From: Alberto.daSilva at rmb.co.za [mailto:Alberto.daSilva at rmb.co.za]
Sent: Friday, October 18, 2002 8:36 AM
To: mimedefang at lists.roaringpenguin.com
Subject: RE: [Mimedefang] Spam to inactive accounts



Greetings,

>> I've been thinking along those lines as well for some time now.  My only
>> humble thought was that I would use a file, almost like a whitelist, to
>> store recipient names, whether the recipient is valid or not, plus a
value
>> similar to a TTL that would allow caching of this information.  The
names
>> and TTL values would be checked, added, deleted, or have their TTL
values
>> renewed (for example, if their current TTL is half the original, then
>> re-check recipient and update values).  I was thinking that this would
save
>> the effort of checking every recipient real-time, but also allow for
>> automatic updating of the recipients, without having to rely that the
>> destination server is always available.

Maybe I'm missing the point, but is this not duplicating functionality
that exists in sendmail?

Properly configured accessdb/virusertable/aliases will achieve exactly
this.

> I think this is a very good idea. Since the file might grow quite large
> on some systems, this could also be expanded upon to allow multiple
> storage formats (flat text file, sql via DBI, dbm files, ldap, etc)
> which would allow for faster queries if needed. You could also provide
> "none" as a storage, and have every check done fresh.

Sendmail accessdb/virtusertable/aliases can be configured for flat text
file,
sql, dbm, ldap, etc, for real-time support of large active/whitelist/user
lists.

It also support dynamic refresh via (newaliases/makemap).

The trick is extracting a active/white/user list from your backend system
and formatting it into accessdb/virtusertable/aliases.

Alberto

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