Repotting report

Tue Feb 5 01:21:27 UTC 2008

In a message written on Mon, Feb 04, 2008 at 07:50:50PM -0500, Kevin Loch wrote:
> There is an interesting variation in what records are returned for a
> standard 512 byte request (dig ns . @[x].root-servers.net):
> 
> A,C,D,E,F,G,I,J: return the same 10 A records and 4 AAAA records in the
> same order every time.  They never return A records for K,L,M and never
> get AAAA records for K,M.
> 
> B: returns all 13 A records in random order and then two AAAA records
> in random order.  This allows all records to be returned with equal
> weight within each record type.
> 
> H,K,L,M: return all 13 A records in static order and then A and F AAAA
> records so H,J,K,M AAAA records are never returned.
> 
> Tested with dig 9.4.1-p1 on a v6 enabled system.

I concur.  An interesting thing I noticed that doesn't really cause
an operational problem but may confuse some people is their behavior
is also quite different when queried for "any".  If your a lazy
admin like me who is used to typing "dig any foo" for testing you
may try "dig any . @[a-m].root-servers.net."

When I do that, I get the following response:

a, c, d e, f, g, i and j return 1 SOA, 8 A, and 3 AAAA's (the first 3).
b, h, l, k, and m return 1 SOA, 13 A, no AAAA records.

If you make this mistake you might think b, h, l, k and m have no
IPv6 data, which is wrong.  Querying with NS (as nameserver would
do) clearly shows that.

While a cosmetic problem, I fear it may confuse a number of admins
as the troubleshoot problems in the near future.

-- 
       Leo Bicknell - bicknell at ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
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