The Oreilly book wrong, or what am I missing??
Simon at wretched.demon.co.uk
Mon Dec 9 10:34:57 UTC 2002
> I am going nuts.
Technically thats off topic ;-)
> I have a copy or "DNS and BIND" by O'Reilly, and I am currently on the
> chapter covering different types of queries: recursive and iterative.
For iterative read "non-recursive" as on page 27
The resolver sends a recursive query to server A.
Server A sends a different type of query to server B, C, D, E
This is how servers B, C, D, E know how to send a referral back,
rather than lookup the answer themselves!
Recursive means the querier requires the server (A) to perform
the recursion, iterative means give me a referral if you don't
know the answer.
So yes the server that receives a "recursive" query, performs
"non-recursive" (iterative queries) to produce an answer.
In reality the difference is the "recursion desired" bit is
switched off. You can experiment with this using "dig +norec",
and look at the flags section of the answer for "RD" "RA" and
"AA" (recursion desired, recursion available, and authortiative
> This info is taken from O'Reilly's DNS and BIND book pages 28-30, which
> seem to be flawed.
Cricket's example looks good to me, although calling it
"iterative" is a tad confusing. Anyone betting it confused
people before, henced the bracketed "iterative in non-recursive"
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