Radek Mrskos wrote:
Ok, but this is exactly what do not belongs to this list. *.mail.ru (many others also) is a spamer domain. If the postmaster of *.rr.com, *.net.br, *.com.br calls you to enter his ranges, will you enter it?
194.67.23.0/24 does not equal the full set of *.mail.ru hostnames.
Similarly, dnswl.org contains three /24s for uol.com.br (see http://www.dnswl.org/search.pl?s=3633). Now this is not a statement that uol.com.br is all nice and cosy, but it's a statement of the fact that the postmaster for uol.com.br told us that these are the ranges for the mailservers (and we verified that using eg senderbase.org).
Since such ranges are usually not as trustworthy as /32s of well-respected mailserver operators, dnswl.org lists such ranges with a score of "none"; for all practical reasons, this should translate into "do not greylist, since there is most likely a legitimate mailserver at the other end who will retry anyway".
Yes, whitelisting incurs the risk of missing some spam. But this risk is usually lower than catching a non-spam in a spamfilter.
-- Matthias