Tunneling techniques such as configured tunnel,6to4,ISATAP and Teredo are common mechanism in the early deployment of IPv6 to connect between two isolated IPv6 Lans or host by using the IPv4 infrastructure,we focused on Teredo tunnel has been designed to encapsulate IPv6 packet in UDP using IPv6-in-UDP-in-IPv4 technology.Though,Teredo tunnel raised some security threats including source routing exploits at the Teredo client from IPv6 routing headers risk.Since source routing in IPv6 header could be exploited by either external orinternal attackers,we believed our TCPA algorithm plays an impact in preventing potential attacks.TCPA is bassed on the filtration principle of machting.it operates on the Teredo client to deny the IPv6 packets which have routing header addresses unles the user allows these addresses traverse through it.The TCPA was implemented as a simulation in a real environment and the result showed that the propossed method of efficient and its logic sounds enought to protect Teredo client from attackers.