PMDF System Manager's Guide
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4.4.2 A Semi-restricted Mailing List

This example will discuss an example of a somewhat restricted list. Subscription requests are referred to a list owner. Only members of the list can post directly to the list; if others attempt to post, their postings will be referred to the list owner. Such a list definition in the PMDF alias file might be: 


group-list:        group-list-expand@process 
group-list-expand: <PMDF_MAILSERV_MAIL_DIR:group-list.dis, \
                    [MODERATOR_ADDRESS] group-list-owner@example.com, \
                    [MODERATOR_LIST] PMDF_MAILSERV_MAIL_DIR:group-list.dis, \
                    [USERNAME] group-list-owner, \
                    [HEADER_ADDITION] PMDF_TABLE:group-list-headers.txt, \
                    group-list-owner@example.com, \
                    group-list@example.com 
group-list-request: MAILSERV
Because the entire list is used for the [MODERATOR_LIST] argument, anyone already on the list can post directly to the list. But attempted postings from anyone else will be referred to the [MODERATOR_ADDRESS] argument, group-list-owner@example.com

The above list definition references a file of headers to be added to messages posted to the list; such a file might be: 


List-Help: <mailto:mailserv@example.com?body=help> (MAILSERV Instructions), 
     <mailto:group-list-owner@example.com?subject=help> (List Manager) 
List-Subscribe: 
     <mailto:group-list-owner@example.com?subject=subscribe%20group-list> 
List-Unsubscribe: 
     <mailto:mailserv@example.com?body=unsubscribe%20group-list> 
List-Post: <mailto:group-list-owner@example.com> (List Moderator) 
List-Owner: <mailto:group-list-owner@example.com?Subject=group-list>

Only group-list-owner@example.com will be permitted to subscribe users to the list. group-list-owner can also unsubscribe other users from the list. And group-list-owner@example.com will have to confirm any SUBSCRIBE or UNSUBSCRIBE commands; that is, when group-list-owner@example.com sends a SUBSCRIBE or UNSUBSCRIBE request to MAILSERV, MAILSERV will send back to group-list-owner@example.com a message containing a cookie string, which group-list-owner@example.com will need to include in a second, confirming message in order for the command to actually be performed. Users can unsubscribe themselves, but attempts to unsubscribe others will be referred to the group-list-owner. Only members of the list will be permitted to request the list membership file, and MAILSERV will require that such requests be confirmed with a second request message including a cookie string that MAILSERV sends out to the supposed requestor address. 


MAILSERV_ACCESS 
 
  SUBSCRIBE|group-list|group-list-owner@example.com|*             $K$V$Y  (1)
  SUBSCRIBE|group-list|group-list-owner@example.com                 $K$Y  (2)
  SUBSCRIBE|group-list|*|*                $*group-list-owner@example.com  (3)
  SUBSCRIBE|group-list|*                  $*group-list-owner@example.com  (4)
  UNSUBSCRIBE|group-list|group-list-owner@example.com|*           $K$V$Y  (5)
  UNSUBSCRIBE|group-list|group-list-owner@example.com               $K$Y  (6)
  UNSUBSCRIBE|group-list|*|*            $Y$*group-list-owner@example.com  (7)
  UNSUBSCRIBE|group-list|*                                            $Y  (8)
  SENDLIST|group-list|group-list-owner@example.com                    $Y  (9)
  SENDLIST|group-list|*     $X$<PMDF_MAILSERV_MAIL_DIR:group-list.dis     (10)
  PURGELIST|group-list|group-list-owner@example 
MAILSERV_LISTS 
 
  group-list                              $Agroup-list-owner@example.com  (11)

More specifically:

  1. This entry explicitly allows group-list-owner@example.com to subscribe others to the list; a later entry, , will cause third-party subscribe attempts from any other sending address to be redirected to group-list-owner@example.com. Note the use of $K; this means that any subscription will not be performed immediately, but rather MAILSERV will send back a challenge message to (due to the $V group-list-owner@example.com asking him to confirm the subscription.
  2. This entry explicitly allows group-list-owner@example.com to subscribe himself to the list; a later entry, , will cause direct subscribe attempts from any other sending address to be redirected to group-list-owner@example.com. Note the use of $K; this means that such a subscription will not be performed immediately, but rather MAILSERV will send back a challenge message to group-list-owner@example.com asking him to confirm the subscription.
  3. This entry causes third party subscribe attempts to be redirected to group-list-owner@example.com.
  4. This entry causes direct subscribe attempts to be redirected to group-list-owner@example.com.
  5. This entry allows group-list-owner@example.com to unsubscribe other addresses from the list. Note the use of $K; this means that any unsubscription will not be performed immediately, but rather MAILSERV will send back a challenge message to (due to the $V) group-list-owner@example.com asking him to confirm the unsubscription.
  6. This entry allows group-list-owner@example.com to unsubscribe himself from the list. Note the use of $K; this means that any unsubscription will not be performed immediately, but rather MAILSERV will send back a challenge message to group-list-owner@example.com asking him to confirm the unsubscription.
  7. This entry causes third-party unsubscribe attempts to be redirected to group-list-owner@example.com. Since third party unsubscribes are disallowed by default, an alternative would be to not put in any entry and get the default behavior of disallowing them. But it can be useful for group-list-owner to know about attempted third party unsubscribes; for instance, users whose addresses change can be attempting to unsubscribe their old addresses.
  8. This entry allows general users to unsubscribe themselves. This is allowed by default, so strictly speaking this entry is not necessary; however, it is included for completeness and clarity.
  9. This entry allows group-list-owner@example.com to get a copy of the list membership file.
  10. This entry allows members of group-list to get a copy of the list membership file; because of the $X in the entry, they will not get comment lines by default.
  11. This entry allows group-list-owner@example.com to purge the list membership file of comment lines (such as MAILSERV comment lines showing unsubscribed users).
  12. This MAILSERV_LISTS entry specifies that MAILSERV responses to user messages to MAILSERV regarding group-list will have a From: address of group-list-owner@example.com.

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