Quanah Gibson-Mount:
> One of our customers has an interesting setup where they did the following:
>
> a) Created 50 users
>
> b) Added a secondary address for the 50 users to an external server with 50
> users (So any email sent to user@server also gets copied to user@server2).
>
> c) Created a list with the 50 users as members. Lists are just a simple
> ldap member: of list.
>
> If an email is sent to the list:
>
> The 50 users on the server each get a copy
>
> The 50 users on the second server get two copies
>
> I've verified I can recreate this issue with a list of 30 users with the
> same configuration. I don't see it with a list of 25 users. I'm sure
> there's a postconf key that would control this, but I haven't had any luck
> tracking it down. Thoughts welcome. ;)
Suggestions:
1) Look at the maillog files of primary and secondary server, with
particular attention to the nrcpt and orig_to fields.
2) 50 Is a magical number; it is the default_destination_recipient_limit
(the number of recipients per SMTP mail transaction). When a queue
file has more than 50 SMTP recipients, these will be delivered in
more than one mail transaction.
3) Postfix tries to preserve the x-original-to address by default,
meaning it will not eliminate duplicate recipients of the same
message that differ in the x-original-to address.
Wietse
