On Thu, 15 Nov 2007, Odhiambo Washington wrote:

> > Speaking of which, does anyone have any good tips to share on how to 
> > write an ACL for incoming Mailman traffic, which (say) rejects 
> > post-DATA for messages which are not from list members?  (Obviously 
> > only for [EMAIL PROTECTED]; not for -owner nor -request, for example).
> 
> Mailman should do that if properly configured, no? There must be 
> information from the Mailman FAQ (and even tips on the net) on how to 
> properly configure Mailman lists to prevent abuse.

It doesn't reject at SMTP-time, but if a list is configured appropriately, 
messages not from list members can be automatically accepted, discarded, 
rejected with message, or held for moderation.  In the latter case, the 
moderator can choose to accept, discard or reject.  So what happens is 
down to how the list server manager and list owner have configured and 
operate the list.

Back to the original question, Mailman stores its list memberships in 
python pickles, but I suppose you could periodically dump a text file out 
of them and consult on a per-list basis at SMTP time before accepting a 
message.  If the list membership changes rapidly, you'd need to dump out 
text file correspondingly.  Or I imagine you could interface something to 
Exim that will read the pck file directly, but you'd need to be aware that 
you are bypassing the mechanisms built into Mailman itself.

Of course all this has the fundamental flaw that authentication to send to 
the list is done by sending email address, which of course is trivially 
forgeable.  Certain members of this list will testify to this, having 
suffered the indignity of seeing fraudelent messages 'from' them on the 
list.

There are a few other potential mechanisms if you are determined to let 
list members be able to post to a list without moderation oversight; a 
'secret' list posting address known only to members, a 'secret' list 
password which must be used when posting, or each member has their own 
'secret' address which they must use to post to the list.  None are 
implemented widely, probably mostly because it just makes list posting 
more tedious, and apart from occasional incidents, we mostly get along 
fine without the obstructions.

Jethro.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jethro R Binks
Computing Officer, IT Services
University Of Strathclyde, Glasgow, UK

-- 
## List details at http://lists.exim.org/mailman/listinfo/exim-users 
## Exim details at http://www.exim.org/
## Please use the Wiki with this list - http://wiki.exim.org/

Reply via email to