HELP - Multiple Emails !!

[Matthew Seaman]

On Wed, Aug 20, 2003 at 09:02:28AM -0700, Jayakumar wrote:
> Hi all,
> I am new to FreeBSD we are trying to sendmail using
> BSD. We made changes to "access" file to allow only
> the particular IP address to relay. We are sending
> around 2000- 4000 emails at a time, but the receipents
> are getting multiple emails for the same message. 
> 
> Can anyone please help me in solving this problem ?
> 
> Do I need to configure some other files?


How exactly are you sending these messages? Do you use the
/etc/mail/aliases file to list the addresses of all of the members of
this mailing list, or by some other mechanism?  Are you using any
mailing list management software like Mailman
(http://www.list.org/index.html) or listserv (http://www.lsoft.com/)?

I doubt that the contents of the /etc/mail/access.db have any impact
on your recipients seeing multiple copies of an e-mail.  

Sendmail should suppress duplicates -- that is if exactly the same
recipient is mentioned multiple times in the envelope recipient list
of a single message, then that recipient will only get one copy
delivered.  The envelope recipient list consists the names of the
recipients after processing through the local aliases or virtuser or
other tables, and need not have any resemblance at all to the
recipients given in the message headers, although they generally start
out as what's in the To: or Cc: or Bcc: lines of the message header.
Generally when there are multiple recipients for a message all at the
same remote site, sendmail will batch those together, and use a single
transaction to send the message body once with envelope receipt-to set
to just that sub-list of the addresses.

However, the duplicate supression can be foiled in several ways:

  i) Multiple distinct addresses for the same person in the mailing
     list.  In this case, you're doing exactly what that subscriber
     has requested, and (in an ideal world) they should fix things
     themselves before complaining to you.

     (Some mailing lists modify the messages they send to add a
     statement showing the address that message was sent to, but that
     defeats the mechanism to avoid sending the message multiple times
     to the same site.)

 ii) Some of the addresses on your list actually funnel into other
     lists or mail aliases at other sites, outside either your or the
     addressees' control.  You'ld have to contact the admins of the
     sites in question to sort that problem out.

iii) Your mailing list software is actually taking the list of
     addressees and either sending the message to each address
     individually or dividing the addresses into groups in order to
     send them.  In this case, there's nothing sendmail can do to
     suppress duplicates -- you should curate your mailing list
     carefully to ensure that addresses aren't duplicated in the list.

If you examine /var/log/maillog after sending out to your mailing
list, you should be able to work out if your message is being sent as
in (iii) -- each message would have a separate message ID in that case.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
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