IPv6 prefix from T-Mobile USA used but not announced in BGP (2607:7700::/32)

Aaron Hopkins lists at die.net
Wed Apr 27 20:16:28 UTC 2016

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

> 2607:7700:0:25::4e00:605b

4e00:605b ->

                                     -- Aaron

More information about the NANOG mailing list