--- loncom/lonnet/perl/lonnet.pm	2005/08/09 16:33:03	1.650
+++ loncom/lonnet/perl/lonnet.pm	2005/09/01 06:45:30	1.653
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.650 2005/08/09 16:33:03 albertel Exp $
+# $Id: lonnet.pm,v 1.653 2005/09/01 06:45:30 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -767,6 +767,13 @@ sub validate_access_key {
 }
 
 # ------------------------------------- Find the section of student in a course
+sub devalidate_getsection_cache {
+    my ($udom,$unam,$courseid)=@_;
+    $courseid=~s/\_/\//g;
+    $courseid=~s/^(\w)/\/$1/;
+    my $hashid="$udom:$unam:$courseid";
+    &devalidate_cache_new('getsection',$hashid);
+}
 
 sub getsection {
     my ($udom,$unam,$courseid)=@_;
@@ -3767,6 +3774,8 @@ sub modify_student_enrollment {
 		   $cdom,$cnum);
     unless (($reply eq 'ok') || ($reply eq 'delayed')) {
 	return 'error: '.$reply;
+    } else {
+	&devalidate_getsection_cache($udom,$uname,$cid);
     }
     # Add student role to user
     my $uurl='/'.$cid;
@@ -4420,8 +4429,10 @@ sub EXT {
     if ($realm eq 'user') {
 # --------------------------------------------------------------- user.resource
 	if ($space eq 'resource') {
-	    if (defined($Apache::lonhomework::parsing_a_problem) ||
-		defined($Apache::lonhomework::parsing_a_task)) {
+	    if ( (defined($Apache::lonhomework::parsing_a_problem)
+		  || defined($Apache::lonhomework::parsing_a_task))
+		 &&
+		 ($symbparm eq &symbread()) ) {
 		return $Apache::lonhomework::history{$qualifierrest};
 	    } else {
 		my %restored;
@@ -5880,19 +5891,26 @@ BEGIN {
     }
     close($config);
     # FIXME: dev server don't want this, production servers _do_ want this
-    #&get_iphost();
+    &get_iphost();
 }
 
 sub get_iphost {
     if (%iphost) { return %iphost; }
+    my %name_to_ip;
     foreach my $id (keys(%hostname)) {
 	my $name=$hostname{$id};
-	my $ip = gethostbyname($name);
-	if (!$ip || length($ip) ne 4) {
-	    &logthis("Skipping host $id name $name no IP found\n");
-	    next;
+	my $ip;
+	if (!exists($name_to_ip{$name})) {
+	    $ip = gethostbyname($name);
+	    if (!$ip || length($ip) ne 4) {
+		&logthis("Skipping host $id name $name no IP found\n");
+		next;
+	    }
+	    $ip=inet_ntoa($ip);
+	    $name_to_ip{$name} = $ip;
+	} else {
+	    $ip = $name_to_ip{$name};
 	}
-	$ip=inet_ntoa($ip);
 	push(@{$iphost{$ip}},$id);
     }
     return %iphost;