To:
dnsop@cafax.se
From:
"D. J. Bernstein" <djb@cr.yp.to>
Date:
16 Jul 2003 06:09:31 -0000
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Subject:
Re: regarding the respsize draft: preferring glue of certain types
Randy Bush writes: > this assumes that the transport available between the dns resolver and > the dns server is correlated to the transport between the application > client and the server. No. The issue is delegations, particularly big delegations such as the DNS root servers' delegation of .com to 13 different DNS servers. Both levels are DNS; there isn't any ``application client'' here. Suppose that a .com DNS server has both A and AAAA. I don't see why the root servers would ever want to provide both addresses. Specifically: * If the query shows up through IPv4, why bother sending the .com server's AAAA address? Obviously the resolver is capable of reaching the A address. * If the query shows up through IPv6, why bother sending the .com server's A address? Obviously the resolver is capable of reaching the AAAA address. Vixie was suggesting omitting AAAA's past the 512-byte limit in the first case, and A's past the 512-byte limit in the second, but I don't see any use of the extra records even if they all fit into 512 bytes. ---D. J. Bernstein, Associate Professor, Department of Mathematics, Statistics, and Computer Science, University of Illinois at Chicago #---------------------------------------------------------------------- # To unsubscribe, send a message to <dnsop-request@cafax.se>.