RFC 6751, "Native IPv6 behind IPv4-to-IPv4 NAT Customer Premises Equipment (6a44)", October 2012

Errata ID: 3384
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Andreas Cudok
Date Reported: 2012-10-18
Verifier Name: Nevil Brownlee
Date Verified: 2014-01-20

Section 6.5.3 says:

CR-2 IPv6/IPv4 PACKET FROM A HOST OF THE SAME SITE
 
    <figure omitted>

If ALL the following conditions are satisfied (i.e., the packet comes
from a 6a44 client of the same site), the 6a44 client MUST
decapsulate the inner packet and treat it as a received IPv6 packet:
(1) the IPv4 packet contains a complete UDP datagram (protocol = 17,
offset = 0, more-fragment bit = 0); (2) both ports of the UDP
datagram are the 6a44 port, and the UDP payload is an IPv6 packet
(UDP length of at least 40 octets, version = 6); (3) the IPv6 source
address is one of the same site (the first 80 bits match those of the
6a44-client IPv6 address; (4) its last 32 bits are equal to the IPv4
source address; (5) the IPv6 destination address is the 6a44-client
IPv6 address.

It should say:

CR-2 IPv6/IPv4 PACKET FROM A HOST OF THE SAME SITE
 
    <figure omitted>

If ALL the following conditions are satisfied (i.e., the packet comes
from a 6a44 client of the same site), the 6a44 client MUST
decapsulate the inner packet and treat it as a received IPv6 packet:
(1) the IPv4 packet contains a complete IPv6 packet (protocol = 41,
offset = 0, more-fragment bit = 0); (2) the IPv6 source
address is one of the same site (the first 80 bits match those of the
6a44-client IPv6 address); (3) its last 32 bits are equal to the IPv4
source address and the IPv4 source address starts with the IPv4 link
prefix; (4) the IPv6 destination address is the 6a44-client
IPv6 address; (5) its last 32 bits are equal to the IPv4 destination
address.

Notes:

Bullet (2) in the original text has to be discarded because UDP is not used for IPv6 encapsulation in the case described by CR-2. The following bullet numbers got decremented by 1. Bullets (1) and (2)-(4) (after renumbering) were changed and bullet (5) was added taking information from CT-2 in section 6.5.2.

Thanks to Andreas for finding this.
In CR-2 of page 21 the text is inconsistent with the figure, which is right.
The proposed correction does eliminate this bug.

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