I'v been saying about need for more radical change in mail protocol for years now on mailing lists. I'd rather work on smtp itself, but some people who were involved in original protocol do not want any serious changes to what they'v done, though its clear that abuse and other holes with current system is creating too many problems.
In any case, by next ietf meeting in san francisco, I'll bring complete proposal for new protocol and might even try some practical tests. I do still believe that smtp can be saved, but not without more complex authentication system during delivery of email and that can't be done with current protocol design or current available extension process. Also were there any discussions or more complete discription of this algorithm for checking if host had sent an email and if so is this available on website or archive to read more about? If answer is yes, can somebody send me url or approximate date of discussions so I could lookup in archives. And am I correct here in understanding what was proposed is that smtp conversation id be such that receiving mail server could verify with sender (callback?) that it deed indeed initiate the email. If so I do not quite understand how MD5 helps there, plus I see quite a few problems with creating some special mx-like record in dns just for verification. If this is indeed what was proposed its better to go with paul vixie's proposal of mailfrom dns record - http://www.vix.com/~vixie/mailfrom.txt or http://www.ietf.org/internet-drafts/draft-church-dns-mail-sender-02.txt On Fri, 6 Dec 2002, Marc Schneiders wrote: > On Fri, 6 Dec 2002, at 13:41 [=GMT-0800], Fred Baker wrote: > > > I think it was Steve Bellovin that suggested a procedure for reducing the > > utility of spoofing source addresses in emails; if not, it was me and I > > happened to suggest something his favorite algorithm fit into, by having a > > host in each mail domain (mailid.example.com) be able to assert that its > > domain had or had not sent an email within a given recent time period > > whose MD5 hash, when divided by <vector of prime numbers> resulted in > > <vector of remainders>. I could write that up in an internet draft if folks > > think it makes sense. That would be a more global procedure that didn't > > require a PKI and only addressed spoofed addresses. > > Spammers would be the first to set up your mailid host. They will have > had years of experience to find holes in the system before you've > convinced everyone to adopt or accept the mailid. > > It might be easier to write a new protocol to succeed email, instant > messaging, mobile phones (something useful in itself) with built-in > abuse control from the start.
