On Wed, Apr 27, 2016 at 02:38:41PM -0700, Ca By wrote: > What behavior do you expect when an ipv6only node connects to an ipv4only > node , which is the tmobile case? How is that address of the address > report?
As far as I know, IPv4-only DHT nodes do not directly communicate with IPv6-only DHT nodes, I don't see how this would be possible in general. The code of the DHT client is here: https://github.com/savoirfairelinux/opendht > On Wednesday, April 27, 2016, Baptiste Jonglez <bapti...@bitsofnetworks.org> > wrote: > > > On Wed, Apr 27, 2016 at 01:16:28PM -0700, Aaron Hopkins wrote: > > > On Wed, 27 Apr 2016, Baptiste Jonglez wrote: > > > > > > >While doing statistics on the participants of a public DHT, I was > > > >surprised to see some IP addresses that are not present in the DFZ: > > > > > > I believe those are used by T-mobile's 464XLAT (RFC 6877) implementation. > > > > > > Recent Android on T-mobile is IPv6-only and has no ability to connect to > > > raw IPv4 addresses. T-mobile's DNS servers are only asked by these > > devices > > > to translate hostnames to IPv6 addresses. If they can't find an IPv6 > > > address, they will look up the IPv4 address for a hostname, and pack it > > into > > > the bottom 32 bits of an IPv6 address that routes to a IPv6-to-IPv4 NAT > > > device. > > > > Thanks, I had forgotten that DNS64 is possible without using the > > well-known prefix. The encoded IPv4 addresses seem to belong to other > > peers of the DHT. > > > > So, if this is basically DNS64/NAT64, these IP addresses should not be > > seen as source or destination address outside of T-Mobile's network, and > > are not attached to the interface of any device. > > > > I can see two possible explanations: > > > > 1/ packets with src or dest IP in 2607:7700::/32 somehow escaped > > T-Mobile's network, without being translated back to IPv4. They caused > > other DHT nodes to believe they have incoming peers in 2607:7700::/32. > > > > 2/ there is an interesting bug in the DHT software when run behind 464XLAT > > (btw, the DHT is dual-stack and supports IPv6 just fine) > > > > I still wonder how this can happen, because the DHT does not use DNS at > > all... > > > > Baptiste > >
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