Enhancing the Security of a Private Network by Using A Multi-level Hierarchical NAT Scheme

Nowadays, attacks coming from the Internet are posing serious threats to the hosts in an institution, campus, company, etc. The Network Address Translator (NAT) is a device that allows a host in a private network to interact with the hosts on the public Internet. Due to the property of NAT, unless a host that is behind a NAT actively contacts a host on the Internet, hosts on the Internet cannot actively reach the host behind the NAT. In this work, we exploit NATs and propose a multi-level hierarchical NAT scheme to protect and enhance the security of a private network. We have designed and implemented our scheme over P4 programmable hardware switches. Experimental results show that our scheme functions correctly and provides high throughput, low latency, and high stability. In addition, according to our tests, our scheme works correctly with most existing network applications.