On Tue, Oct 03, 2006 at 09:03:49PM +0530, Ramprasad wrote:
So a SPF lookup is heavier than a rbl lookup ?
Some SPF record are well designed, in which case the anwer would be: no.
Unfortunately, some records are like:
"v=spf1 a mx ptr include:this include:that ip4:192.0.2.1 -all"
Now, when a spammer connects, chances are the only match will
occur on "all", so the entire record needs to be processed
including all a, mx, ptr lookups, the two included records,
which may contain even more a or mx records.
This is far more than just one DNS lookup, and a rbl lookup is
usually just one, maybe two, lookups.
HTH
Alex
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