for l2j can be something like that, or you can make own flood protector:
Index: java/com/l2jserver/gameserver/network/clientpackets/MoveBackwardToLocation.java
===================================================================
--- java/com/l2jserver/gameserver/network/clientpackets/MoveBackwardToLocation.java (revision 3701)
+++ java/com/l2jserver/gameserver/network/clientpackets/MoveBackwardToLocation.java (working copy)
@@ -82,6 +82,10 @@
L2PcInstance activeChar = getClient().getActiveChar();
if (activeChar == null)
return;
+
+ if (!activeChar.getFloodProtectors().getServerBypass().tryPerformAction("protected_packets"))
+ return;
+
// Correcting targetZ from floor level to head level (?)
// Client is giving floor level as targetZ but that floor level doesn't
// match our current geodata and teleport coords as good as head level!