diff --git a/src/opnsense/scripts/OPNsense/CaptivePortal/cp-background-process.py b/src/opnsense/scripts/OPNsense/CaptivePortal/cp-background-process.py
index 816825d09..1ae97fee4 100755
--- a/src/opnsense/scripts/OPNsense/CaptivePortal/cp-background-process.py
+++ b/src/opnsense/scripts/OPNsense/CaptivePortal/cp-background-process.py
@@ -33,6 +33,7 @@ import ujson
 import time
 import syslog
 import traceback
+import subprocess
 from lib import Config
 from lib.db import DB
 from lib.arp import ARP
@@ -190,6 +191,7 @@ def main():
     """ Background process loop, runs as backend daemon for all zones. only one should be active at all times.
         The main job of this procedure is to sync the administration with the actual situation in the ipfw firewall.
     """
+    last_cleanup_timestamp = 0
     bgprocess = CPBackgroundProcess()
     bgprocess.initialize_fixed()
 
@@ -198,6 +200,11 @@ def main():
             # open database
             bgprocess.db.open()
 
+            # cleanup old settings, every 5 minutes
+            if time.time() - last_cleanup_timestamp > 300:
+                bgprocess.db.cleanup_sessions()
+                last_cleanup_timestamp = time.time()
+
             # reload cached arp table contents
             bgprocess.arp.reload()
 
@@ -211,6 +218,9 @@ def main():
             # close the database handle while waiting for the next poll
             bgprocess.db.close()
 
+            # process accounting messages (uses php script, for reuse of Auth classes)
+            subprocess.call(['/usr/local/opnsense/scripts/OPNsense/CaptivePortal/process_accounting_messages.php'])
+
             # sleep
             time.sleep(5)
         except KeyboardInterrupt:
diff --git a/src/opnsense/scripts/OPNsense/CaptivePortal/lib/db.py b/src/opnsense/scripts/OPNsense/CaptivePortal/lib/db.py
index 6c2bef8d1..452cbf8f3 100644
--- a/src/opnsense/scripts/OPNsense/CaptivePortal/lib/db.py
+++ b/src/opnsense/scripts/OPNsense/CaptivePortal/lib/db.py
@@ -355,3 +355,49 @@ class DB(object):
         else:
             self._connection.commit()
             return 'update'
+
+    def cleanup_sessions(self):
+        """ cleanup removed sessions, but wait for accounting to finish when busy
+        """
+        cur = self._connection.cursor()
+        cur.execute(""" delete
+                        from cp_clients
+                        where cp_clients.deleted = 1
+                        and not exists (
+                            select  1
+                            from    accounting_state
+                            where   accounting_state.zoneid = cp_clients.zoneid
+                            and     accounting_state.sessionid = cp_clients.sessionid
+                            and     accounting_state.state <> 'STOPPED'
+                        )
+                        """)
+        cur.execute(""" delete
+                        from    accounting_state
+                        where   not exists (
+                            select  1
+                            from    cp_clients
+                            where   cp_clients.zoneid = accounting_state.zoneid
+                            and     cp_clients.sessionid = accounting_state.sessionid
+                        )
+                    """)
+        cur.execute(""" delete
+                        from    session_info
+                        where   not exists (
+                            select  1
+                            from    cp_clients
+                            where   session_info.zoneid = cp_clients.zoneid
+                            and     session_info.sessionid = cp_clients.sessionid
+                        )
+                    """)
+
+        cur.execute(""" delete
+                        from    session_restrictions
+                        where   not exists (
+                            select  1
+                            from    cp_clients
+                            where   session_restrictions.zoneid = cp_clients.zoneid
+                            and     session_restrictions.sessionid = cp_clients.sessionid
+                        )
+                    """)
+
+        self._connection.commit()
diff --git a/src/opnsense/scripts/OPNsense/CaptivePortal/process_accounting_messages.php b/src/opnsense/scripts/OPNsense/CaptivePortal/process_accounting_messages.php
new file mode 100755
index 000000000..cb42537d8
--- /dev/null
+++ b/src/opnsense/scripts/OPNsense/CaptivePortal/process_accounting_messages.php
@@ -0,0 +1,96 @@
+#!/usr/local/bin/php
+<?php
+/**
+ *    Copyright (C) 2015 Deciso B.V.
+ *
+ *    All rights reserved.
+ *
+ *    Redistribution and use in source and binary forms, with or without
+ *    modification, are permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice,
+ *       this list of conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *
+ *    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ *    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ *    AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ *    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *    POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+require_once('script/load_phalcon.php');
+
+use OPNsense\Core\Config;
+use OPNsense\Auth\AuthenticationFactory;
+
+// open database
+$database_filename = '/var/captiveportal/captiveportal.sqlite';
+$db = new SQLite3($database_filename);
+
+// query all sessions with client restrictions
+$result = $db->query('
+    select      c.zoneid
+    ,           c.sessionid
+    ,           c.username
+    ,           c.authenticated_via
+    ,           c.deleted
+    ,           c.created
+    ,           accs.state
+    from        cp_clients c
+    inner join  session_restrictions sr on sr.zoneid = c.zoneid and sr.sessionid = c.sessionid
+    left join   session_info si on c.zoneid = si.zoneid and c.sessionid = si.sessionid
+    left join   accounting_state accs on accs.zoneid = c.zoneid and accs.sessionid = c.sessionid
+    order by    c.authenticated_via
+    ');
+
+// process all sessions
+while($row = $result->fetchArray(SQLITE3_ASSOC) ){
+    $authFactory = new OPNsense\Auth\AuthenticationFactory;
+    $authenticator = $authFactory->get($row['authenticated_via']);
+    if ($authenticator != null) {
+        if ($row['state'] == null) {
+            // new accounting state, send start event (if applicable)
+            $stmt = $db->prepare('insert into accounting_state(zoneid, sessionid, state)
+                                  values (:zoneid, :sessionid, \'RUNNING\')');
+            $stmt->bindParam(':zoneid', $row['zoneid']);
+            $stmt->bindParam(':sessionid', $row['sessionid']);
+            $stmt->execute();
+            if (method_exists($authenticator,'startAccounting')) {
+                // send start accounting event
+                $authenticator->startAccounting($row['username'], $row['sessionid']);
+            }
+        } elseif  ($row['deleted'] == 1 && $row['state'] != 'STOPPED') {
+            // stop accounting, send stop event (if applicable)
+            $stmt = $db->prepare('update accounting_state
+                                  set state = \'STOPPED\'
+                                  where zoneid = :zoneid
+                                  and   sessionid = :sessionid');
+            $stmt->bindParam(':zoneid', $row['zoneid']);
+            $stmt->bindParam(':sessionid', $row['sessionid']);
+            $stmt->execute();
+            if (method_exists($authenticator,'startAccounting')) {
+
+                $time_spend = time() - $row['created'];
+                $authenticator->stopAccounting($row['username'], $row['sessionid'], $time_spend);
+            }
+        } elseif ($row['state'] != 'STOPPED') {
+            // send interim updates (if applicable)
+            if (method_exists($authenticator,'updateAccounting')) {
+                // send interim update event
+                $time_spend = time() - $row['created'];
+                $authenticator->updateAccounting($row['username'], $row['sessionid'], $time_spend);
+            }
+        }
+    }
+}
+$db->close();