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Re: Open Letter to D-Link about their NTP vandalism
Matthew Black wrote:
This is way OT.On Mon, 10 Apr 2006 23:23:06 -0700 (PDT) Matt Ghali <email@example.com> wrote:On Tue, 11 Apr 2006, Simon Lyall wrote:Everyone here runs spam filters. Many times a day you tell a remote MTA you've accepted their email but you delete it instead. Explain the difference?
Inline rejection -- best
Notification after the fact -- Worst, but sometimes unavoidable
Silent Disacard -- better then blanket notifications
Try to limit the second in preference for the first.
For anything in which your detection mechanism's accuracy is high enough, you can probably perform the last without much worry.
Dont do that. Notify the recpient if anything. Unfortunately they may learn to ignore such notifications, especialy if your system is fairly accurate. I advise against such "quarantine;store;notify;wait;delete" systems precisely because of this.mattoAre you suggesting that we configure our e-mail servers to notify people upon automatic deletion of spam?
Yes, a 550 after completion of DATA with <cr><lf>.<cr><lf> is perfectly acceptable and preferable. Legit senders should hang around for the half minute or so to receive 220, and illegits will tend to drop the connection after being told 550.Frequently, spam cannot be properly identified until closure of the SMTP conversation and that final 200 mMESSAGE ACCEPTED...or do you think that TCP/IP connection should be held open until the message can be scanned for spam and viruses just so we can give a 550 MESSAGE REJECTED error instead of silently dropping it?
I do that all the time with barely a no thanks. My wife complains that I am rude to do so. I think not.Because most spam originates from a bogus or stolen sender address, notification creates an even bigger problem. What's next: asking for permission to hang up on telemarketers?
The problem is in the word "most". With regards to anti-virus, "most" becomes "well upwards of 99%", and as such silent discard is more acceptable.
matthew black network services california state university, long beach