On Fri, Mar 07, 2003 at 10:36:43AM -0600, wayne wrote:
It should be pointed out that DNSBLs, including domain specific
DNSBLs, use the *absence* of an A record as an indication that IP
address is ok. Negative DNS responses are generally not cached
anywhere near as log as positive results. I do not know if this was a
design decision on the part of DNSBLs, or just a result of it being
easier to create that way.
Both presence and absence of a record can be spoofed. Presence
is spoofed by the fake record itself, absence by a bogus CNAME.
regards
Hadmut
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