The IESG has approved the following document: - 'IPv4 Residual Deployment via IPv6 - a Stateless Solution (4rd)' (draft-ietf-softwire-4rd-10.txt) as Experimental RFC This document is the product of the Softwires Working Group. The IESG contact persons are Brian Haberman and Ted Lemon. A URL of this Internet Draft is: http://datatracker.ietf.org/doc/draft-ietf-softwire-4rd/ Technical Summary: This document specifies a stateless softwire IPv4 over IPv6 Migration Solution called 4rd. Using the 4rd solution IPv4 packets are transparently carried across IPv6 networks (reverse of 6rd [RFC5969] in which IPv6 packets are statelessly tunneled across IPv4 networks). While IPv6 headers are too long to be mapped into IPv4 headers, so that 6rd requires encapsulation of full IPv6 packets in IPv4 packets, IPv4 headers can be reversibly translated into IPv6 headers in such a way that, during IPv6 domain traversal, UDP packets having checksums and TCP packets are valid IPv6 packets. IPv6-only middle boxes that perform deep-packet- inspection can operate on them, in particular for port inspection and web caches. Working Group Summary: The working group had active discussion on the draft and the current text of the draft is representative of the consensus of the working group. Document Quality: The document has received adequate review. The Document Shepherd has no concerns about the depth or breadth of these reviews. Certain aspects of the scheme have also been reviewed by the 6man working group due to the concerns with the address format. These concerns were successfully resolved. Personnel: Suresh Krishnan is the document shepherd. Ted Lemon is the responsible AD. RFC Editor Note: This document is one of a set of five softwire documents that should be published with sequential RFC numbers. The numbering should be in the following order: draft-ietf-softwire-lw4over6 draft-ietf-softwire-map draft-ietf-softwire-map-dhcp draft-ietf-softwire-map-t draft-ietf-softwire-4rd