Notification of an error in delivery to a mailing list is sent to the original sender as bounced mail. Although this behavior is desirable for most mail delivery, it can have undesirable results for mailing lists. Because the list is maintained locally, it does not make sense for an error message to be sent to a remote sender. That sender is likely to be puzzled or upset and unable to fix the problem. A better solution is to force all error messages to be sent to a local user, no matter who sent the original message.
When sendmail processes errors during delivery, it looks to
see whether an "owner" was defined for the mailing list. If one was
defined, errors are sent to that owner rather than to the sender.
The owner is defined by prefixing the original
mailing list alias
with the phrase owner-
, as shown in the following code:
nuts: :include:/home/lists/nuts.list owner-nuts: george
Here, nuts
is the name of the mailing list. If an error
occurs in attempting delivery to the list of recipients in
the file /home/lists/book.list
, sendmail
looks for an alias called owner-nuts
(the original
name prefixed with owner-
). If sendmail finds
an owner (here, george
),
it sends error notification to that owner rather than
to the original sender.
Generally, it is best to have the owner-
of a list
be the same as the owner of the mailing-list file, since that user
is best suited to correct errors as they appear.
To ensure that all errors in mailing lists are handled by someone, an owner of owners should also be defined. That alias usually looks like this:
owner-owner: postmaster
If sendmail cannot deliver an error message to
the owner-
of a mailing list, it instead delivers it
to the owner-owner
.
Beginning with V8
sendmail, a single alias expansion is done on the owner-
of any :include:
list, and that expansion is made the address of the
envelope sender:
nuts: :include:/home/lists/nuts.list owner-nuts: nuts-request nuts-request: george
Here, with V8 sendmail, the envelope sender for mail sent to nuts
will be nuts-request
(a single-level alias expansion), rather than
george
(a multiple-level alias expansion).
As a side effect, with V8 sendmail, mail sent to owner-
anything
will have the envelope-sender address set to a single alias expansion of
owner-owner
. This can be confusing, so always stress to users that they
should mail the maintainer of a list with the -request
suffix instead
of the owner-
prefix.