On (01/11/17 12:43), Eric Dumazet wrote: > > On Wed, 2017-01-11 at 14:59 -0500, Sowmini Varadhan wrote: > > > I think the RFC states somewhere that you should never ever > > send out a v4 mapped address on the wire. > > Can you point the exact RFC ? > > https://tools.ietf.org/html/rfc2765 seems to allow just that.
I have not read the details of 2765, but from a cursory look, it talks about "IPv4-translatable addresses", not v4-mapped addrs, and says, "The address translation mechanisms for the stateless and the stateful translations are defined in [RFC6052]" It's also not clear to me that 2765 warrants the use of these as ip6 src, or ip6 dst, or the target(s) of NS/NA. https://www.rfc-editor.org/rfc/rfc4038.txt refers to security considerations about sending v4-mapped addrs on the wire Looks like these security considerations are discussed in https://tools.ietf.org/html/draft-itojun-v6ops-v4mapped-harmful-02 In general, I think BSD and Solaris (and probably most router implementations, esp the BSD-based ones) will not allow v4 mapped addresses as src or dst of ip6 packets. > Jonathan issue is about terminating such flows in TCP stack, which is > likely not needed/useful. sure. but if you configure the v4 mapped address as a src addr "everything should be fine!" --Sowmini
