Quoting Les Mikesell <les@xxxxxxxxxxxxxxxx> Date: Fri, 04 Feb 2005 17:38:19 > How do you know what IP's are dynamic or when someone else > reallocates them? You assume that somebody else has more or less correct database. Usually various DNSBL databases that have lists of open relays and known spammers, have these list too. They don't have *all* dynamic ranges (only detected, reported by someone else, or reported by ISP itself). From time to time you'd get false positive. Usually some poor guy who bought (rented would be more appropriate term) single static IP address cheap for his ADSL line, and couldn't afford any better. Or from time to time an range that was used for dynamic addresses in the past, but is now used for static (sometimes it takes long time for those lists to be updated for this kind of changes, unless range was reported by ISP itself). Personally, I don't like using those lists for direct blocking (but I do like using them with scoring tools, such as SpamAssassin, where existance of such record only affects the score, but is not enough on its own to block the message). The reason being that while there is less false negatives than with SpamAssassin, there is also more false positives. That is only my experience, somebody else might have different experience. -- Aleksandar Milivojevic <amilivojevic@xxxxxx> Pollard Banknote Limited Systems Administrator 1499 Buffalo Place Tel: (204) 474-2323 ext 276 Winnipeg, MB R3T 1L7
