Wow thats all about fragmentarion settings (Packetfragmentationthreshold/ipmtu/tunnelmtu/mtu/mrru/mru/maxmtu/ipreassemblytimeout and many others that i wont mention here) but if anyone needs just lemme know! but the truth is my system was being targeted by those attacks and i couldnt find the best setting(values) for those and others but after studying those in depth i could figure out a way to end up with such attacks!! blocking in firewall rules was just useless for these kind of attacks!! and i really microsoft should rethink about a way to stop with those overflows without the user have to sweat buckets like me!!! anyways this is just a informative for all n(Sigh) Regards, RR