PowerPoint Presentation

Proving Non-existence of a wildcard (2)

f. SOA É

*.fA

e.f AÉ

*.e.f.AÉ

d.e.fAÉ

*.d.e.f.AÉ

c.d.e.fAÉ

*.c.d.e.f.AÉ

b.c.d.e.f AÉ

*.b.c.d.e.fA

We have to prove that all these wildcards are NOT in the zone

These are the NXT RRs and what

they proof.

b.c.d.e.f NXT f

(no *.b.c.d.e.f nor a.b.c.d.e.f)

c.d.e.f NXT b.c.d.e.f

(no *.c.d.e.f.)

d.e.f. NXT c.d.e.f.

(no *.d.e.f.)

e.F NXT d.e.f.

(no *.e.f.)

f. NXT e.f.

(no *.f)

In this case you will only have to return

b.c.d.e.f NXT a

Since it already proves that there is no

closer match for the wildcard.

b.c.d.e.f cancels *.f, *.e.f, *.d.e.f , etc.


	É it is because of this rule.
			If B.X and *.X appear in the zone with origin X then a query for Z.X would return the wildcard data. The wildcard answer would not apply for question for B.X, A.B.X or X.

	One more example:
	$origin foo.
	@ SOA
	NXT a
	a A
	a NXT a.b
	a.b A
	a.b NXT a.c
	a.c A
	a.c NXT a.b.c
	a.b.c A
	a.b.c NXT @

	QNAME: d.b.c QTYPE A

	a.b.c.foo NXT foo (proofs that d.b.c does not exist)
	*a.c.foo NXT a.b.c.foo (proofs that .b.c does not exist)**
	*a.b.foo NXT a.c.foo (proofs that .c does not exit)**
	*foo NXT a.foo (proofs that does not exist)**

	Bind9.3s20020722 does not optimize for that yet.