I have no clue how you to get a "how do i hack hotmail" from his question as it is abstruse and not being presented into english very well. But i will clarify a bit, i think? Ip is internet protocol , udp is a part of ip as is tcp, udp has no way to correct itself and is connectionless. If packets are lost they are gone and that is it. Tcp has error correction so that if packets get lost on the way they are resent and also holds a connection. And well it really has not much to do with the insecurity/security of yahoo and msn messanger. The actual programs are what cause security risks not the protocol used , I assume udp is used due to its speed?? and not due to a lack of security (please someone correct me. I don't know if i have answered your question as i am not sure if i know what it is or if i can even???