Hello Thomas,
{calculation of DNS response sizes is a topic for the IETF DNSOP WG
<http://www.ietf.org/html.charters/dnsop-charter.html>. For the basic
issues, the archives of the DNSOP mailinglist may help, or even more so
(apart from direct replies) one of the DNS related Usenet newsgroups.}
> A query send to one of the root servers with a long name (length 255) shows
> that
> the answer is 511 bytes, returning one A and 13 NS records. My question is: W
>hy
> are all 13 NS returned?
The protocol requires (RFC 2181, 5.2) that RRSets be handed out completely.
Everything else would sooner or later result in "funny" effects and severe
operational problems. It is, however, arguable, whether or not the "A" RR
is really needed. Currently deployed software may lead to a "yes" here.
-Peter
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