Kai Schaetzl wrote:
Matt Kettler wrote on Mon, 12 Dec 2005 20:17:04 -0500:
Using greylisting you'd delay their mail, but they'd be able to deliver even if
they still are in the RBL if they retry after the greylist timer expires.
That makes only sense if you greylist *only* hosts on these lists. This looks
rather elegant, but you completely loose the real effectiveness of greylisting.
Greylisting works perfectly against all those zombies (and the few spam blasters)
which are *not* on these lists. Using it only together with RBLs makes greylisting
very ineffective in my eyes.
I haven't used greylisting myself, but consider implementing it.
However, I'm usually told "greylisting is great, but without
whitelisting you will have to many false-positives, eg. newsletter, etc.".
Personally, I don't trust DNS-blacklists to deny messages and I don't
trust greylisting and wouldn't have the time to create and maintain
whitelists.
However, greylisting only IPs that are found on DNS-blacklists should
give those IPs a "second chance" and hopefully reduce maintainance.
In theory, at least.
Does anybody have experience with this approach? It's quite off-topic
here, so it would be better to reply off-list.
--
CU,
Patrick.
