On Wed 27 Apr 2016 at 11:14:15 +0200, to...@tuxteam.de wrote: > On Wed, Apr 27, 2016 at 09:53:31AM +0100, Brian wrote: > > On Wed 27 Apr 2016 at 20:31:17 +1200, cbannis...@slingshot.co.nz wrote: > > > > > On Sat, Apr 23, 2016 at 12:57:08PM -0500, John Hasler wrote: > > > > > Thanks for making me think of that and the fact that over the last 10 > > > > > years, the only ham its seen are its mistakes. So this question might > > > > > have had the seeds of something to help. :) > > > > > > > > My scripts copy all new non-spam to a ham directory which is fed to > > > > sa-learn every night and then the contents of both the ham and the > > > > spam directories are deleted. > > > > > > IIRC, it seems pointless feeding your mail through a spam filter > > > if you're downloading it from your ISP/email provider. > > > > I think you are assuming the ISP provides a spam filtering service and > > you are happy to entrust the deletion of your mail to it. > > There is still some truth to the above: > > The most effective measure against spam these days is rejecting > the mail up front (i.e. while the SMTP session is active). This > way a (hopefully rare!) false positive is rejected in a way the > sender can act on it.
I'd agree with this but would suggest the (vast) majority of users have their mail delivered to a POP3 or IMAP account. Any rejection at SMTP time is left up to the ISP and a user is usually unaware of this or has no control over it. > Once you got the mail it's too late. Either you have to generate > a bounce (not a good idea these days, because real spam will have > bogus headers and the bounce will hit a poor unsuspecting victim), > or you have to look into the spam anyway, or the spam disappears > in a black hole (again not a good idea, since in the false > positive case the sender will newer know). > > Therefore once your ISP has accepted the mail for you it's kinda > "too late" -- they better have a good spam filtering setup in > which you have some influence (the spam filter will only work > if it has a notion of what *you* consider to be spam/ham). Indeed, the transaction is complete and the mail delivered once the ISP accepts it. All a user can do is try to avoid downloading unwanted mail. Leaving filtering to the ISP is fraught as many offer only a "take it or leave it" service, again with no user control. Even more do not allow an opt-out and no matter what the quality of the service a deleted mail is a deleted mail. I'd rather make my own mistakes. And have. :)
