diff --git a/readconfig.pl b/readconfig.pl
index eac3824..fe8e0db 100644
--- a/readconfig.pl
+++ b/readconfig.pl
@@ -4,22 +4,7 @@
 #
 # Copyright 2001 Wilmer van der Gaast (lintux@lintux.cx)
 #
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
-#
+# Updated for marker-aware config writing.
 
 my( @info, @conf, @rawconf, $l );
 
@@ -52,6 +37,7 @@ $info[47] = 'Trustee files';
 $info[50] = 'Conversion tables';
 $info[60] = 'MAX_CONNECTIONS';
 $info[61] = 'MAX_NW_VOLS';
+$info[62] = 'Reserved';
 $info[63] = 'MAX_DIR_BASE_ENTRIES';
 $info[68] = 'USE_MMAP';
 $info[69] = 'HANDLE_ALL_SAP_TYPS';
@@ -161,6 +147,42 @@ sub section_of_line( $ )
     return( '' );
 }
 
+sub grouped_section_key( $ )
+{
+    my $sec = $_[0];
+
+    if( $sec >= 100 && $sec <= 106 ) { return '100-106'; }
+    if( $sec >= 200 && $sec <= 202 ) { return '200-202'; }
+    if( $sec >= 210 && $sec <= 211 ) { return '210-211'; }
+    if( $sec >= 300 && $sec <= 302 ) { return '300-302'; }
+
+    return $sec;
+}
+
+sub build_marker_map()
+{
+    my( %map, $line, $sec, $key );
+
+    foreach $line ( @conf )
+    {
+	$sec = section_of_line( $line );
+	next if $sec eq '';
+
+	$key = grouped_section_key( $sec );
+	push( @{ $map{$key} }, $line );
+    }
+
+    # Keep SYS as first entry in section 1
+    if( defined( $map{'1'} ) )
+    {
+	my @sys = grep( /^1 SYS /, @{ $map{'1'} } );
+	my @rest = grep( !/^1 SYS /, @{ $map{'1'} } );
+	$map{'1'} = [ @sys, @rest ];
+    }
+
+    return %map;
+}
+
 sub writeconfig_compact()
 {
     my( $i, $l );
@@ -183,13 +205,63 @@ sub writeconfig_compact()
     close( CONF );
 }
 
+sub writeconfig_markers()
+{
+    my( %secmap, %emitted );
+    my( $line, $active_key, $inside_active );
+
+    %secmap = build_marker_map();
+    $inside_active = '';
+
+    open( CONF, '>' . $mars_config ) or die "Could not write $mars_config: $!";
+
+    foreach $line ( @rawconf )
+    {
+	if( $line =~ /^\s*#\s*>>>\s*SMARTHOOK\s+SECTION\s+([0-9]+(?:-[0-9]+)?)\s+ACTIVE\s+BEGIN/i )
+	{
+	    $active_key = $1;
+	    $inside_active = $active_key;
+
+	    print CONF $line;
+
+	    if( defined( $secmap{$active_key} ) )
+	    {
+		foreach my $entry ( @{ $secmap{$active_key} } )
+		{
+		    print CONF $entry . "\n";
+		}
+	    }
+
+	    $emitted{$active_key} = 1;
+	    next;
+	}
+
+	if( $line =~ /^\s*#\s*<<<\s*SMARTHOOK\s+SECTION\s+([0-9]+(?:-[0-9]+)?)\s+ACTIVE\s+END/i )
+	{
+	    $inside_active = '';
+	    print CONF $line;
+	    next;
+	}
+
+	if( $inside_active ne '' )
+	{
+	    # Skip old content inside ACTIVE blocks completely.
+	    next;
+	}
+
+	print CONF $line;
+    }
+
+    close( CONF );
+}
+
 sub writeconfig_preserve_layout()
 {
     my( %secmap, %written, @sections, $sec, $line, $sysline );
+    my( $heading_sec );
 
     sortconfig();
 
-    # Keep SYS as the first entry in section 1.
     $sysline = ( grep( /^1 SYS /, @conf ) )[0];
     if( defined( $sysline ) )
     {
@@ -210,16 +282,34 @@ sub writeconfig_preserve_layout()
 
     foreach $line ( @rawconf )
     {
+	if( $line =~ /^\s*#.*Section\s+([0-9]+)\b/i )
+	{
+	    $heading_sec = $1;
+
+	    foreach $sec ( sort { $a <=> $b } keys( %secmap ) )
+	    {
+		next if $written{$sec};
+		next if $sec > $heading_sec;
+
+		if( defined( $secmap{$sec} ) )
+		{
+		    foreach my $entry ( @{ $secmap{$sec} } )
+		    {
+			print CONF $entry . "\n";
+		    }
+		}
+		$written{$sec} = 1;
+	    }
+	}
+
 	$sec = section_of_line( $line );
 
-	# Preserve comments and blank lines exactly as they were.
 	if( $sec eq '' )
 	{
 	    print CONF $line;
 	    next;
 	}
 
-	# Replace each section only once, at its first occurrence.
 	if( ! $written{$sec} )
 	{
 	    if( defined( $secmap{$sec} ) )
@@ -231,12 +321,8 @@ sub writeconfig_preserve_layout()
 	    }
 	    $written{$sec} = 1;
 	}
-
-	# Skip the original config line because the updated section
-	# has already been emitted.
     }
 
-    # Append sections that did not exist in the original file.
     @sections = sort { $a <=> $b } keys( %secmap );
     foreach $sec ( @sections )
     {
@@ -253,12 +339,28 @@ sub writeconfig_preserve_layout()
     close( CONF );
 }
 
+sub config_has_smart_markers()
+{
+    foreach my $line ( @rawconf )
+    {
+	if( $line =~ /SMARTHOOK\s+SECTION/i )
+	{
+	    return 1;
+	}
+    }
+    return 0;
+}
+
 sub writeconfig()
 {
     if( defined( $smart_compact_nwservconf ) && $smart_compact_nwservconf )
     {
 	writeconfig_compact();
     }
+    elsif( config_has_smart_markers() )
+    {
+	writeconfig_markers();
+    }
     else
     {
 	writeconfig_preserve_layout();