Index: includes/Block.php
===================================================================
--- includes/Block.php	(revision 17592)
+++ includes/Block.php	(working copy)
@@ -434,10 +434,12 @@
 
 	/**
 	* Autoblocks the given IP, referring to this Block.
-	*@param $autoblockip The IP to autoblock.
-	*@return Whether or not an autoblock was inserted.
+	* @param string $autoblockip The IP to autoblock.
+	* @return bool Whether or not an autoblock was inserted.
 	*/
 	function doAutoblock( $autoblockip ) {
+		global $wgAutoblockWhitelist;
+
 		# Check if this IP address is already blocked
 		$dbw =& wfGetDb( DB_MASTER );
 		$dbw->begin();
@@ -445,6 +447,14 @@
 		if ( !$this->mEnableAutoblock ) {
 			return;
 		}
+		
+		$unsignedip = IP::toUnsigned($autoblockip);
+		foreach ($wgAutoblockWhitelist as $range) {
+			$range = IP::parseCIDR($range);
+			$bits = 32 - $range[1];
+			if ($range && $unsignedip >> $bits << $bits == $range[0])
+				return;
+		}
 
 		$ipblock = Block::newFromDB( $autoblockip );
 		if ( $ipblock ) {
Index: includes/DefaultSettings.php
===================================================================
--- includes/DefaultSettings.php	(revision 17593)
+++ includes/DefaultSettings.php	(working copy)
@@ -859,6 +859,11 @@
 $wgSysopRangeBans		= true; # Allow sysops to ban IP ranges
 $wgAutoblockExpiry		= 86400; # Number of seconds before autoblock entries expire
 $wgBlockAllowsUTEdit    = false; # Blocks allow users to edit their own user talk page
+# Dynamic AOL IPs are almost never used by the same person twice in a row, so
+# there's no point in autoblocking them.  These are from
+# <http://webmaster.info.aol.com/proxyinfo.html>, but others may be added if
+# desired.
+$wgAutoblockWhitelist   = array( '64.12.96.0/19', '149.174.160.0/20', '152.163.240.0/21', '152.163.248.0/22', '152.163.252.0/23', '152.163.96.0/22', '152.163.100.0/23', '195.93.32.0/22', '195.93.48.0/22', '195.93.64.0/19', '195.93.96.0/19', '195.93.16.0/20', '198.81.0.0/22', '198.81.16.0/20', '198.81.8.0/23', '202.67.64.128/25', '205.188.192.0/20', '205.188.208.0/23', '205.188.112.0/20', '205.188.146.144/30', '207.200.112.0/21' );
 
 # Pages anonymous user may see as an array, e.g.:
 # array ( "Main Page", "Special:Userlogin", "Wikipedia:Help");