SIPNAT (Source-IP NAT)
Businesses, online service organizations, governments, and family websites all require global presence and continuous, on-demand availability. Customers and clients have to be able to initiate contact with the servers, not the other way around. Unfortunately, with traditional port-mapped NAT (NAPT), this is impossible because the translation parameters for each flow must be established by the internal network node. I describe a new proposal for enabling such incoming translations, called “source-IP NAT” (SIPNAT), which relies on DNS to establish the required parameters for the flow translation.
Because of its natural fit with the typical DNS model of application interaction, SIPNAT is transparent to existing IPv4 and IPv6 nodes, does not require dual-stack or tunneling, and enables connectivity even for protocols that do not use ports (e.g., GRE and ICMP). I also describe recent analytical results and performance improvements that result from simple extraction of fields of certain payloads.
Charles E. Perkins is a Technical Fellow at WiChorus, Inc. investigating mobile wireless networking and dynamic configuration protocols. He is serving as document editor for the mobile-IP working group of the Internet Engineering Task Force (IETF), and is author or co-author of standards-track documents in the mip4, mext, manet, dhc, seamoby (Seamless Mobility) and autoconf working groups. He is an editor for several ACM and IEEE journals for areas related to wireless networking. In addition to designing advanced features for LTE ane WiMax products, he continues strong interest with research actitivies for ad hoc networking and scalability and performance issues related to Internet access for billions of portable wireless devices.
Before joining WiChorus, Charles was Nokia Fellow and also briefly associated with Nokia Siemens. Before joining Nokia, Charles was a research staff member at IBM T.J. Watson Research center for 13 years.