                                  Courier 0.46

   Contents of this NEWS file:

     [1]Overhauled Courier home page. 
     [2]Sender Policy Framework       
     [3]Older stuff                   

  Overhauled Courier home page

   [4]http://www.courier-mta.org has undergone a facelift. It sports improved
   navigation, and better organizations. Mozilla and Firefox users have an
   extra bonus: the leftmost button in the navigation bar is a pop-down menu
   that allows easy navigation between the major sections: [5]Courier,
   [6]Courier-IMAP, [7]SqWebMail, and [8]Maildrop. Internet Explorer does not
   have the required level of CSS support (no support for transparent
   background and absolute positions), so the popdown menu does not work with
   MSIE.

  Sender Policy Framework

   Courier now implements the evolving SPF protocol for validating E-mail
   addresses. The ESMTP HELO, MAIL FROM, and the From: headers can be
   validated with SPF. There are several options that control the flexible
   SPF implementation. SPF support is implemented through the bofh
   configuration file.

  Older stuff

   Starting with Courier 0.45, the default configuration enables metadata
   dot-locking. In previous version metadata dot-locking (IMAP_USELOCKS
   setting in the imapd configuration file) is disabled by default.
   Dot-locking was, and still is optional. When enabled, its value-added
   functionality is elimination of certain non-critical race conditions with
   concurrent access. Dot-locking is now enabled by default due to its proven
   record of "mostly harmless", and that it now provides added benefit with
   ACLs and shared folders. However, when upgrading from an earlier version,
   the existing configuration setting is left in place; only new installation
   of Courier will default to enabled dot-locking.

  Shared folders and access control lists

   New to Courier 0.45 are the ACL (access control list) IMAP extension, and
   ACL-based virtual shared folders. Courier 0.45 implements both the
   existing ACL specification, RFC 2086, as well as an experimental
   implementation of the second draft revision of the ACL specification.
   Virtual shared folders is a different implementation of shared folders
   that supplements an older implementation in previous versions. The older,
   POSIX permission-based shared folders are still implemented and supported.
   Here's a summary of the differences between the two shared folder
   mechanisms:

      POSIX-based shared folders              ACL shared folders              
                                  May be used with virtual accounts only;     
     May be used with system      cannot be used on systems that have         
     accounts only^1              end-user login shell access: bypassing ACLs 
                                  and accessing the folders directly is       
                                  trivial                                     
     Access rights based on       Access rights based on IMAP access control  
     traditional POSIX filesystem lists                                       
     permissions                  
     Sharable folders must be set A site-specific process must be installed   
     up manually, using the       to compile an index of all virtual          
     "maildirmake" command        mailboxes; afterwords, individual users may 
                                  create and manage shared folders themselves 

       ^1 This is because access rights are governed by filesystem
       permissions. POSIX shared folders may also be used with virtual
       accounts, but it will not be possible to grant read-only access to
       shared folders, and everyone will be able to delete messages from
       shared folders (instead of only the creator of each message)

   After installation, read the "maildiracl" manual page for a brief overview
   of access control lists.

   Read "maildir/README.sharedfolders.html" for information on configuring
   virtual shared folders

References

   Visible links
   1. file:///home/mrsam/src/courier/NEWS.html#intro
   2. file:///home/mrsam/src/courier/NEWS.html#spf
   3. file:///home/mrsam/src/courier/NEWS.html#other
   4. http://www.courier-mta.org/
   5. http://www.courier-mta.org/
   6. http://www.courier-mta.org/imap/
   7. http://www.courier-mta.org/sqwebmail/
   8. http://www.courier-mta.org/maildrop/
