Fujitsu Limited Keio Univ. Keio Univ. Keio Univ. This document specifies SA46T Address Translator (SA46T-AT) specification. SA46T-AT enable access to IPv4 only host from IPv6 host. IPv4 host is identified as SA46T global address in IPv6 address space. The address assigned to IPv4 host may be global IPv4 address or private IPv4 address. SA46T-AT does not support access to IPv6 host from IPv4 only host.