Hello!
When I first bothered with configuring a 6to4 address on my server a couple
of years ago, I also tried to add that to the pool, but got the following:
2002:xxxx:yyyy::z
Bad IP address: 6TO4
As recommended for comments and questions, I wrote to Ask Bjørn Hansen
for an explanation, but he just said that this topic was not for discussion
and redirected me to this mailing list as the only source of information.
Quite some time passed since then, one of my IPv4 addresses has changed,
so I retried again recently, but the result was no different.
If someone here has any insight on why 6to4 (and probably other transitional
technologies) addresses are not eligible to be included in the pool, it
would
be interesting to know the reasoning behind this blacklisting.
Yes, I do understand that 6to4 is, by definition, less "straightforward"
than
a "true" IPv6. Theoretically, it may introduce large and asymmetric delays,
decreased reliability. But, practically, is it really any different from
regular networking? If a time server is contacted across the continent,
or even in the same city, who guarantees that the delay will be low and
equal
in both directions, or that the routes taken will ever be the same?
Particularly, when I contact "true IPv6" servers in the same city (to be
more precise, on the same Internet exchange site as my local 6to4 gateway),
delays are in the range from 4 to 7 milliseconds. Taking into account that
typical delays for IPv4 are from 2 to 5 milliseconds (again, within an IX
that my ISPs are connected), I consider the overhead as negligible.
At the same time, I also stumble on IPv6 servers that are allowed in the
pool
while being no more than just a tunnel to a IPv6 broker, with entry nodes
no closer than a few countries away, or even across the ocean, so resulting
delays are as large as 110 milliseconds. Why are those considered any better
than 6to4, if they are actually inferior? If the intention of the pool
masters
is to blacklist any tunneling technology, then why not blacklist all tunnel
providers (including VPN operators), as their addresses are not secret?
But the thing that puzzles me the most is why to blacklist anything at all?
NTP is able to select the best of the best of the best servers automatically
and keep all falsetickers, unreliable and simply too distant servers out.
Then why the pool places own artificial restrictions atop of that?
--
With best regards,
Anton
_______________________________________________
pool mailing list
[email protected]
http://lists.ntp.org/listinfo/pool
