> Robust for what? Spammers? The simple fact of the matter is > that the alternative is to just shut down port 25 given the > growth in both volume and complexity to filter. Finally, a sensible solution! After all, why should any mail server operator accept incoming email from another server without a prior mail peering agreement in place? The email architecture of Simple Mail Transfer Protocol is completely broken and has been largely superceded. Why not begin to turn off services on the problem port? RFC 4409 split off the submission stream from the relay stream, therefore one can reasonably assume that most of the non-spam port 25 traffic is relay. Some of that is customers of an ISP, who therefore have an implicit or explicit mail peering agreement, relaying through the ISP's mailserver. And some of it is anonymous relays delivering messages to what appears to be the final destination. If we get rid of the anonymity for relays delivering to final destination, i.e. gmail.com sending a message for example@xxxxxxx to an aol.com mailserver, then most of the spam stream goes away. At that point, we only have to worry about spam which subverts the submission mechanism or some other weakness in the system. Anonymous relaying on port 25 is a known weakness. Why can't we close this gap? Do we need a new port assignment for mail peer relaying? Do we need to fix the SMTP-AUTH weaknesses? Do we need an upgrade to ESMTP that is incompatible with previous SMTP versions to make a clear break with the past? Is there an informational RFC that describes the overall email architecture that is provided by the various IETF protocols? Such a document could help frame the discussion and identify weaknesses that need further work such as the SPF/DKIM bandaids. We have gotten to the present situation because various people doing work on the problem have blinders on as that focus on one narrow area of the problem. We need to describe the totality of the situation, point out what works fine or has already been fixed, and suggest a way forward for fixing the problems. By the way, SPAM is not the problem. The problem is anonymity and lack of accountability. I believe that the email architecture can be fixed so that unknown people can still email me anonymously, and I won't be able to identify them without cooperation from my ISP, but at the same time, if these people are abusing the system, my ISP can follow a chain of accountability to the sender, or to the point in the chain where bilateral trust relationships have broken. In such a scenario, I am confident that SPAM will still exist, but I am also confident that it will no longer be such a firehose, just a dribble. SPAM is not a problem in the email architecture. Lack of a solid chain of accountability formed with bilateral trust agreements is the root problem with the email architecture. --Michael Dillon _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf