[lwip-devel] [bug #65583] DNS lookup should take into account available source IPv6 and IPv4 addresses

[Sly Gryphon]

Follow-up Comment #1, bug #65583 (group lwip):

This bug also breaks DNS64/NAT64 when a client with both IPv6 and IPv4 is
deployed to an IPv6-only network.

Because the client supports both IPv6 and IPv4, it can use a single DNS query
with AF_UNSPEC. This will work correctly if coming from a dual-stack network
to any destination, e.g. an IPv6 only destination will not have an IPv4, so
fall back to IPv6.

However when on an IPv6-only network, calls to a dual-stack destination will
incorrectly get back the IPv4 address.

This includes DNS64/NAT64 configurations for IPv4-only hosts. DNS64 will
generate a synthetic IPv6 address, however because of the hard coded "prefer
IPv4" it is never used -- the (unusable) IPv4 address continues to be used.

i.e. An IPv6-only network is only support with IPv6-only destinations.



    _______________________________________________________

Reply to this item at:

  <https://savannah.nongnu.org/bugs/?65583>

_______________________________________________
Message sent via Savannah
https://savannah.nongnu.org/