diff --git a/add_form.php b/add_form.php
index 1fe4668..338b06d 100644
--- a/add_form.php
+++ b/add_form.php
@@ -159,13 +159,20 @@ class mod_attendance_add_form extends moodleform {
             if (isset($pluginconfig->automark_default)) {
                 $mform->setDefault('automark', $pluginconfig->automark_default);
             }
-            $mform->addElement('text', 'subnet', get_string('requiresubnet', 'attendance'));
-            $mform->setType('subnet', PARAM_TEXT);
-            $mform->addHelpButton('subnet', 'requiresubnet', 'attendance');
-            $mform->disabledif('subnet', 'studentscanmark', 'notchecked');
+            $mgroup2 = array();
+            $mgroup2[] = & $mform->createElement('text', 'subnet', get_string('requiresubnet', 'attendance'));
             $mform->setDefault('subnet', $this->_customdata['att']->subnet);
-            $mform->setAdvanced('subnet');
+            $mgroup2[] = & $mform->createElement('checkbox', 'usedefaultsubnet', get_string('usedefaultsubnet', 'attendance'));
+            $mform->setDefault('usedefaultsubnet', 1);
+            $mform->setType('subnet', PARAM_TEXT);
 
+            $mform->addGroup($mgroup2, 'subnetgrp', get_string('requiresubnet', 'attendance'), array(' '), false);
+            $mform->setAdvanced('subnetgrp');
+            $mform->addHelpButton('subnetgrp', 'requiresubnet', 'attendance');
+
+            $mform->disabledif('usedefaultsubnet', 'studentscanmark', 'notchecked');
+            $mform->disabledif('subnet', 'studentscanmark', 'notchecked');
+            $mform->disabledif('subnet', 'usedefaultsubnet', 'checked');
         } else {
             $mform->addElement('hidden', 'studentscanmark', '0');
             $mform->settype('studentscanmark', PARAM_INT);
diff --git a/classes/structure.php b/classes/structure.php
index 757dfa7..14b484d 100644
--- a/classes/structure.php
+++ b/classes/structure.php
@@ -500,7 +500,12 @@ class mod_attendance_structure {
             !empty($formdata->studentscanmark)) {
             $sess->studentscanmark = $formdata->studentscanmark;
             $sess->studentpassword = $formdata->studentpassword;
-            $sess->subnet = $formdata->subnet;
+            if (!empty($formdata->usedefaultsubnet)) {
+                $sess->subnet = $this->subnet;
+            } else {
+                $sess->subnet = $formdata->subnet;
+            }
+
             if (!empty($formdata->automark)) {
                 $sess->automark = $formdata->automark;
             }
diff --git a/lang/en/attendance.php b/lang/en/attendance.php
index d286ba7..32bf5ca 100644
--- a/lang/en/attendance.php
+++ b/lang/en/attendance.php
@@ -372,10 +372,10 @@ $string['repeaton'] = 'Repeat on';
 $string['invalidsessionendtime'] = 'The end time must be greater than start time';
 $string['deletedgroup'] = 'The group associated with this session has been deleted';
 $string['extrarestrictions'] = 'Extra restrictions';
-$string['requiresubnet'] = 'Students can only record own attendance from these computers.';
+$string['requiresubnet'] = 'Require network address';
 $string['subnetwrong'] = 'Attendance can only be recorded from certain locations, and this computer is not on the allowed list.';
 $string['requiresubnet_help'] = 'Attendance recording may be restricted to particular subnets by specifying a comma-separated list of partial or full IP addresses.';
-$string['defaultsubnet'] = 'Default subnet range';
+$string['defaultsubnet'] = 'Default network address';
 $string['defaultsubnet_help'] = 'Attendance recording may be restricted to particular subnets by specifying a comma-separated list of partial or full IP addresses. This is the default value used when creating new sessions.';
 $string['defaultsettings'] = 'Default attendance settings';
 $string['defaultsettings_help'] = 'These settings define the defaults for all new attendances';
@@ -398,4 +398,5 @@ $string['studentmarking'] = 'Student recording';
 $string['automarktask'] = 'Check for closed attendance sessions that require auto marking';
 $string['autorecorded'] = 'system auto recorded';
 $string['coursesummary'] = 'Course summary report';
-$string['averageattendance'] = 'Average attendance';
\ No newline at end of file
+$string['averageattendance'] = 'Average attendance';
+$string['usedefaultsubnet'] = 'Use default';
\ No newline at end of file
diff --git a/locallib.php b/locallib.php
index 40b40d5..5a82d32 100644
--- a/locallib.php
+++ b/locallib.php
@@ -520,9 +520,10 @@ function attendance_exporttocsv($data, $filename) {
 /**
  * Get session data for form.
  * @param stdClass $formdata moodleform - attendance form.
+ * $param mod_attendance_structure $att - used to get attendance level subnet.
  * @return array.
  */
-function attendance_construct_sessions_data_for_add($formdata) {
+function attendance_construct_sessions_data_for_add($formdata, mod_attendance_structure $att) {
     global $CFG;
 
     $sesstarttime = $formdata->sestime['starthour'] * HOURSECS + $formdata->sestime['startminute'] * MINSECS;
@@ -570,7 +571,11 @@ function attendance_construct_sessions_data_for_add($formdata) {
                     $sess->timemodified = $now;
                     if (isset($formdata->studentscanmark)) { // Students will be able to mark their own attendance.
                         $sess->studentscanmark = 1;
-                        $sess->subnet = $formdata->subnet;
+                        if (!empty($formdata->usedefaultsubnet)) {
+                            $sess->subnet = $att->subnet;
+                        } else {
+                            $sess->subnet = $formdata->subnet;
+                        }
                         $sess->automark = $formdata->automark;
                         $sess->automarkcompleted = 0;
                         if (!empty($formdata->randompassword)) {
@@ -616,7 +621,12 @@ function attendance_construct_sessions_data_for_add($formdata) {
             } else {
                 $sess->studentpassword = $formdata->studentpassword;
             }
-            $sess->subnet = $formdata->subnet;
+            if (!empty($formdata->usedefaultsubnet)) {
+                $sess->subnet = $att->subnet;
+            } else {
+                $sess->subnet = $formdata->subnet;
+            }
+
             if (!empty($formdata->automark)) {
                 $sess->automark = $formdata->automark;
             }
diff --git a/sessions.php b/sessions.php
index 61369b8..73631fc 100644
--- a/sessions.php
+++ b/sessions.php
@@ -73,7 +73,7 @@ switch ($att->pageparams->action) {
         }
 
         if ($formdata = $mform->get_data()) {
-            $sessions = attendance_construct_sessions_data_for_add($formdata);
+            $sessions = attendance_construct_sessions_data_for_add($formdata, $att);
             $att->add_sessions($sessions);
             if (count($sessions) == 1) {
                 $message = get_string('sessiongenerated', 'attendance');
diff --git a/update_form.php b/update_form.php
index 76ab916..e3bc1c1 100644
--- a/update_form.php
+++ b/update_form.php
@@ -49,6 +49,7 @@ class mod_attendance_update_form extends moodleform {
         if (!$sess = $DB->get_record('attendance_sessions', array('id' => $sessionid) )) {
             error('No such session in this course');
         }
+        $attendancesubnet = $DB->get_field('attendance', 'subnet', array('id' => $sess->attendanceid));
         $defopts = array('maxfiles' => EDITOR_UNLIMITED_FILES, 'noclean' => true, 'context' => $modcontext);
         $sess = file_prepare_standard_editor($sess, 'description', $defopts, $modcontext, 'mod_attendance', 'session', $sess->id);
 
@@ -70,6 +71,11 @@ class mod_attendance_update_form extends moodleform {
                 'subnet' => $sess->subnet,
                 'automark' => $sess->automark,
                 'automarkcompleted' => 0);
+        if ($sess->subnet == $attendancesubnet) {
+            $data['usedefaultsubnet'] = 1;
+        } else {
+            $data['usedefaultsubnet'] = 0;
+        }
 
         $mform->addElement('header', 'general', get_string('changesession', 'attendance'));
 
@@ -115,11 +121,21 @@ class mod_attendance_update_form extends moodleform {
             $mform->addHelpButton('studentpassword', 'passwordgrp', 'attendance');
             $mform->disabledif('studentpassword', 'studentscanmark', 'notchecked');
 
-            $mform->addElement('text', 'subnet', get_string('requiresubnet', 'attendance'));
+
+            $mgroup2 = array();
+            $mgroup2[] = & $mform->createElement('text', 'subnet', get_string('requiresubnet', 'attendance'));
+            $mform->setDefault('subnet', $this->_customdata['att']->subnet);
+            $mgroup2[] = & $mform->createElement('checkbox', 'usedefaultsubnet', get_string('usedefaultsubnet', 'attendance'));
+            $mform->setDefault('usedefaultsubnet', 1);
             $mform->setType('subnet', PARAM_TEXT);
-            $mform->addHelpButton('subnet', 'requiresubnet', 'attendance');
+
+            $mform->addGroup($mgroup2, 'subnetgrp', get_string('requiresubnet', 'attendance'), array(' '), false);
+            $mform->setAdvanced('subnetgrp');
+            $mform->addHelpButton('subnetgrp', 'requiresubnet', 'attendance');
+
+            $mform->disabledif('usedefaultsubnet', 'studentscanmark', 'notchecked');
             $mform->disabledif('subnet', 'studentscanmark', 'notchecked');
-            $mform->setAdvanced('subnet');
+            $mform->disabledif('subnet', 'usedefaultsubnet', 'checked');
 
             $mform->addElement('hidden', 'automarkcompleted', '0');
             $mform->settype('automarkcompleted', PARAM_INT);