Re: Source routing -- why not?
Tony Finch <[email protected]>
| Newsgroups | gmane.ietf.mxcomp |
|---|---|
| Message-ID | <[email protected]> |
On Tue, 30 Nov 2004, Alex van den Bogaerdt wrote: > On Tue, Nov 30, 2004 at 10:43:40AM +0000, Tony Finch wrote: > > > > After further deliberation about source routing and SPF, I have come > > > around to the conclusion that Frank is to some degree right, and if > > > you want to use SPF/Sender-ID, you should use source routes. > > > > Source routes require all mail servers to be open relays. > > Why? Source routes don't record the relationship between a@a, b@b, and c@c. In your scenario the message to c@c would start MAIL FROM:<@b:a@a>. A spammer who knows that b is a forwarding host can then spam anyone by sending MAIL FROM:<> RCPT TO:<@b:victim@target>. This is why SRS has all the cryptography, in order to provide a secure replacement for the obsolete and unimplemented RFC821 forward and reverse paths. Tony. -- f.a.n.finch <[email protected]> http://dotat.at/ MALIN HEBRIDES: NORTHEAST 4 OR 5 INCREASING 6. RAIN LATER. GOOD BECOMING MODERATE.