Abstract

In a world where the importance of interconnectivity of devices and networks still grows, it is important for a state of the art Peer-to-Peer system to be able to connect each of its peers together. However, many network devices are located behind a so called NAT (Network Address Translation) device. Although NAT devices might add more security to the private network they create, they are breaking the end-to-end connectivity principle of the internet. Key to gain interconnectivity between peers in todays Peer-to-Peer (P2P) systems is the ability to traverse NAT devices. Hole Punching is a NAT traversal method. It is capable to connect two peers which are using different NAT on a software base and without the need of configuring or extending the functionalities of the used NAT. The following chapters explain, how Hole Punching works, is designed, implemented and tested with the TomP2P framework [24, 31, 28].

[24] Mark O’Neill. The Internet of Things: do more devices mean more risks? Computer Fraud & Security, 2014(1):16 – 17, January 2014.

[28] P. Srisuresh, B. Ford, and D. Kegel. State of Peer-to-Peer (P2P) Communication across Network Address Translators (NATs). RFC 5128, RFC Editor, March 2008. http://www.rfc-editor.org/rfc/rfc5128.txt.

[31] Kuai Xu, Feng Wang, Lin Gu, Jianhua Gao, and Yaohui Jin. Characterizing home network traffic: an inside view. Personal and Ubiquitous Computing, 18(4):967–975, August 2014.