DNS was [Gllug] IPSec

[tet at accucard.com]

>I'm curious; what's a 'large' DNS query? Is that where you store a HUGE
>FQDN, or when you store other stuff in a DNS (like keys for IPSec)? Is it
>only appropriate for lookups or for reverse lookups as well?

DNS queries are almost always small enough to fit in UDP, but
replies to those queries may include multiple responses, plus
additional information such as where to find authoritative answers,
etc.

Interestingly enough, I was just trying to provoke DNS into giving me
a long response to use as an illustration of how it would use TCP where
necessary, but the closest I could come was:

	host -t any hotmail.com e.root-servers.net

which resulted in exactly 512 bytes of data (i.e., the maximum size
allowed in a UDP DNS response). One more byte in the response, and
it would have used TCP instead. Certain domains return larger responses
than others. I picked hotmail.com because I happen to know it has a
large number of MX records.

Tet

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