Provided by: squid-openssl_5.6-1ubuntu3_amd64 bug


       ext_session_acl - Squid session tracking external acl helper.

       Version 1.2


       ext_session_acl [-t timeout ] [-b database ] [-a]


       ext_session_acl  maintains  a  concept  of  sessions by monitoring requests and timing out
       sessions. The timeout is based either on idle use ( -t ) or a fixed period of time ( -T ).
       The  former  is  suitable  for  displaying  terms  and conditions to a user; the latter is
       suitable for the display of advertisements or other notices (both as a splash page  -  see
       config examples in the wiki online). The session helper can also be used to force users to
       re-authenticate if the %LOGIN and -a are both used.


       -t timeout  Idle timeout for any session. The  default  if  not  specified  (set  to  3600

       -T timeout  Fixed  timeout  for  any  session. This will end the session after the timeout
                   regardless of a user's activity. If used with active mode, this will terminate
                   the user's session after timeout , after which another LOGIN will be required.
                   LOGOUT will reset the session and timeout.

       -b path     Path to persistent database. If a file is specified then that single  file  is
                   used  as  the  database.  If  a  path  is  specified,  a  Berkeley DB database
                   environment is created within the directory. The advantage of  the  latter  is
                   better  database  support  between  multiple  instances of the session helper.
                   Using multiple instances of the session helper with  a  single  database  file
                   will  cause synchronization problems between processes.  If this option is not
                   specified the session details will be kept in memory  only  and  all  sessions
                   will  reset each time Squid restarts its helpers (Squid restart or rotation of

       -a          Active mode. In this mode sessions are started by evaluating an acl  with  the
                   argument LOGIN , or terminated by the argument LOGOUT .  Without this flag the
                   helper automatically starts the session after the first request.


       The ext_session_acl helper is a concurrent helper; therefore, the concurrency= option must
       be specified in the configuration.

       Passive session configuration example using the default automatic mode
              external_acl_type  session ttl=300 negative_ttl=0 children=1 concurrency=200 %LOGIN
              acl session external session
              http_access deny !session
              deny_info session

       Then set up to display a  session  startup  page
       and then redirect the user back to the requested URL given in the url query parameter.


       This     program     and     documentation     was    written    by    Henrik    Nordstrom
       <> Andrew Beverley <>


        * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
        * Squid software is distributed under GPLv2+ license and includes
        * contributions from numerous individuals and organizations.
        * Please see the COPYING and CONTRIBUTORS files for details.

       This program and documentation is copyright to the authors named above.

       Distributed under the GNU General Public License (GNU GPL) version 2 or later (GPLv2+).


       Questions on the usage of this program can be sent to the Squid Users mailing list <squid->


       Bug    reports    need    to    be    made    in    English.     See    http://wiki.squid- for details of what you need  to  include  with  your  bug

       Report bugs or bug fixes using

       Report serious security bugs to Squid Bugs <>

       Report   ideas  for  new  improvements  to  the  Squid  Developers  mailing  list  <squid->


       squid(8), GPL(7),
       The Squid FAQ wiki
       The Squid Configuration Manual

                                          9 October 2011                       ext_session_acl(8)