[atlas] v6 support

> i am not understanding why probe 2285 does not seem to even get an ipv6
> address on the in-rack lan, while a whole lot of other devices do.

this mailing list *really* works!  a few minutes after posting the
above, the problem went away, the device got a global ipv6 addy after a
couple of weeks without.

> and 2283 managed to get a v6 address but no gateway, and of course no
> v6dns.

now both are the same, ip addy but claim to have no gateway.  otoh, they
seem to be globally ping6able.  wth?

                   IPv4           IPv6    
Internet Address:  147.28.0.132   2001:418:1:0:220:4aff:fee0:246d
Local Address:     147.28.0.132   2001:df9::220:4aff:fee0:246d/64
Gateway:           147.28.0.1     Undetermined/Unknown
DNS Resolver:      147.28.0.35    Undetermined/Unknown
AS Number:         AS3130         AS3130

                   IPv4           IPv6  
Internet Address:  210.138.216.50 2001:240:6a8:0:220:4aff:fee0:227c
Local Address:     192.168.0.27   2001:240:6a8:0:220:4aff:fee0:227c/64
Gateway:           192.168.0.1    Undetermined/Unknown
DNS Resolver:      192.168.0.1    Undetermined/Unknown
AS Number:         AS2497         AS2497

randy