North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Spam filtering bcps [was Re: Open Letter to D-Link about their NTP vandalism]
On Wed, Apr 12, 2006 at 12:03:51PM -0400, Joe Maimon wrote: > Matthew Black wrote: > > > there's no bandwidth savings from silently dropping the message > > versus providing a 550 rejection. In the best of all worlds, > > it would be nice to give feedback. No system is perfect and a > > false-positive rate of less than one in a million "220" accepted > > messages seems pretty small. > > Let me ask you this simple question: > > If you know at close of DATA whether you are going to actually perform > final delivery, what does it cost you to follow standards and issue a > 550 instead of a 220 and discard it? > > If you use a 550, a real live person sending an email that somehow gets > FP will actually benefit. In today's world, at least with the spamtorrent I see at my clients, that's just untrue. If your filtering is set up well, and you mark an e-mail as SPAM, it almost certainly is (yes, I'll certainly concede FP's exist, but again, it almost certainly doesn't matter that much in that teensy number of occurrences); and 99-plus-percent of spam is emitted from spambots who don't give a $expletive about return status one way or another. If you're worrying about "no-status" in the context of FP's, then your filtering isn't set up well, which really means you've got larger problems. > I am with Suresh on this, just like in the past threads. Search the archive. Though not contradicting what I just wrote, so am I. However, header-forged and multi-chained spam from firehose-like spambots don't play by any of our rules; all they do is blast away in a largely one-way transaction (guess which direction!). A 550 now-a-days has nowhere to "go" (and those "commercial" akak "legit") spamhouses don't wash their lists even on 550's. -- Henry Yen Aegis Information Systems, Inc. Senior Systems Programmer Hicksville, New York
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