Date: Tue, 19 Dec 2006 14:28:54 -0500 (EST) From: Charles Sprickman <spork@bway.net> To: Christopher Hilton <chris@vindaloo.com> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: OpenBSD's spamd. Message-ID: <Pine.OSX.4.61.0612191425220.354@white.nat.fasttrackmonkey.com> In-Reply-To: <45881546.30400@vindaloo.com> References: <200612191347.kBJDlg5c058711@lurza.secnetix.de> <45881546.30400@vindaloo.com>
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On Tue, 19 Dec 2006, Christopher Hilton wrote: > Oliver Fromme wrote: >> Dimitry Andric wrote: >> > Oliver Fromme wrote: >> > > What does stuttering mean? Is it similar to sendmail's >> > > "greet_pause" feature? >> > > See here: >> > http://www.ualberta.ca/~beck/nycbug06/spamd/mgp00014.html >> >> OK, so the answer to my question seems to be "yes". :-) >> > > Actually I'd say it's similar. If you telnet to port 25 on a server that's > using sendmail's greet_pause option I'm assuming that you get nothing for 5 > seconds. OpenSD's Spamd sends the initial greeting at a rate of one character > per second and only accepts data from you at the same rate. It also sets the window size to something like 1 byte. :) Someone had mentioned that this would consume many threads/processes, but that is not the case. Bob explained that spamd runs in a select() loop. I don't totally understand that, but to me it sounds like the same methodology that thttpd used, and that sure scaled up nice. Here's what I think is the latest version of Bob's talk. It's quite good. http://www.ualberta.ca/~beck/nycbug06/spamd/ There's audio available here: http://www.nycbsdcon.org/slides Was the original question "when will the FreeBSD port be updated"?? :) Charles > Through experimentation Bob Beck determined that many spammers were dropping > the connection and forgetting about delivering the mail completely after > short and shorter intervals if the connection was rate limited to 1 character > / sec. When the spammers got down to 3 seconds he modified spamd to stutter > for 10 seconds on any connection. That feature came in on OpenBSD 3.8 > > -- Chris > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >
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