On 05.04.2016 09:42, lst_hoe02--- via Info-cyrus wrote: > > As stated the spam actually reaching our inboxes after around 90% cutoff is > valid DKIM/SPF signed as it is mostly from the big free providers like > Outlook.com, Google and Yahoo. Some other big share is from professional spam > farms with always alternating IP and Domains ranges from all over the world > with also valid DKIM/SPF. Next big share is from educational servers also > mostly valid DKIM/SPF. The tiny rest with around 10% is in fact not DKIM/SPF > signed. > From the valid e-mail around 20% looks like having a valid SPF/DKIM, mostly > professional newsletters not personal mail from customers. > > So No, SPF/DKIM is no useful spam fighting tool at least not in our corner of > the world. >
We seem to be located in the same country (Germany), nevertheless the situation is completely different for us. As I have already reported, we have cut off SPAM by 90% solely by checking for SPF and DKIM, and it looks like we could cut down it by another order of magnitude if we are blacklisting domains which have sent SPF- or DKIM-"signed" SPAM (doing so for a few days, but no exact figures yet). I admit that our situation is somewhat special because we are purely B2B, and I absolutely don't care about a freemail provider being blacklisted. I can't even remember the last time when we got a valid message which has been sent from a freemailer account. Actually, if everybody did SPF or DKIM tests, this finally would force the providers to implement DKIM or SPF the right way. For example, using an individual DKIM signature for every sender of a domain is ridiculously easy (at least when using the opendkim daemon). That would be a great progress because then you could blacklist individual senders instead of the provider. Regards, Binarus ---- Cyrus Home Page: http://www.cyrusimap.org/ List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/ To Unsubscribe: https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus
