SOCKSv5-based IPv4-IPv6 Transition Mechanisms History and Status
RFC1928 "SOCKS Protocol V5," April 1996
Fujitsu Labs. first introduced the idea at NGTRANS, Dec.1997 http://www.ietf.org/proceedings/97dec/97dec-final-73.htm
NEC proposed <draft-kitamura-socks-ipv6-00.txt> "SOCKSv5 Protocol Extensions for IPv6/IPv4 Communication Environment," at STP BOF, August 1998
Fujitsu Labs. distributes an implementation since July 1998
ftp://ftp.kame.net/pub/kame/misc/socks64-v10r3-980623.tgz
Two Independent Implementations
NEC has finished an implementation and is planning to open its source in January 1999 http://www.socks.nec.com/