--- loncom/loncron	2010/08/17 22:22:00	1.86
+++ loncom/loncron	2011/05/14 16:12:53	1.89
@@ -2,7 +2,7 @@
 
 # Housekeeping program, started by cron, loncontrol and loncron.pl
 #
-# $Id: loncron,v 1.86 2010/08/17 22:22:00 raeburn Exp $
+# $Id: loncron,v 1.89 2011/05/14 16:12:53 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -32,6 +32,7 @@ use strict;
 
 use lib '/home/httpd/lib/perl/';
 use LONCAPA::Configuration;
+use LONCAPA;
 use Apache::lonnet;
 use Apache::loncommon;
 
@@ -821,9 +822,12 @@ sub main () {
                 print $fh "$key\n";
             }
             close($fh);
-            my $execpath = $perlvar{'lonDaemons'}.'/lciptables';
-            system("$execpath $tmpfile");
-            unlink($fh);
+            if (&LONCAPA::try_to_lock('/tmp/lock_lciptables')) {
+                my $execpath = $perlvar{'lonDaemons'}.'/lciptables';
+                system("$execpath $tmpfile");
+                unlink('/tmp/lock_lciptables');  # Remove the lock file. 
+            }
+            unlink($tmpfile);
         }
     }
 
@@ -866,12 +870,10 @@ sub main () {
 	&check_delayed_msg($fh);
 	&finish_logging($fh);
 	&log_simplestatus();
-	
-	if ($totalcount>200 && !$noemail) { &send_mail(); }
-    }
-    if (!$justcheckconnections && !$justreload) {
         &write_loncaparevs();
         &write_serverhomeIDs();
+	
+	if ($totalcount>200 && !$noemail) { &send_mail(); }
     }
 }