Am 01.05.2013 08:17, schrieb Marc Perkel: > Looking for tricks. > > I'm working on improving outbound spam filtering and I'm using Exim and > testing for valid recipients doing forward recipient callouts, which I > would like to reduce. > > I'm wondering if there's any tricks to figure out at least some bad > domains or recipients without doing recipient callouts. DNS indicators > that would suggest the recipient is bad. > > Or - open to any suggestions on blocking outbound spam. (I'm filtering > outbound for customers so I don't control the original servers) >
outbound spam filtering is heavy stuff, beside not to produce false positives and/or additional support calls, traditional you may have some border gateway with i.e amavis and kinda quarantaine, but whats really needed is an outbound anomaly analyser ,in my opinion, we ve done some concepts about such , but not released anything after all outbound recipient verfiy will not make you happy as others may firewall you by doing to much recipient testing, but it may be a way for limited domains, know to be problematic , analysed by your log before Best Regards MfG Robert Schetterer -- [*] sys4 AG http://sys4.de, +49 (89) 30 90 46 64 Franziskanerstraße 15, 81669 München Sitz der Gesellschaft: München, Amtsgericht München: HRB 199263 Vorstand: Patrick Ben Koetter, Axel von der Ohe, Marc Schiffbauer Aufsichtsratsvorsitzender: Florian Kirstein
