>-----Message d'origine----- >De : [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED] la part de Bart Mortelmans >Envoy=E9 : vendredi 27 avril 2007 09:41 >=C0 : [email protected] >Objet : [xmail] Re: Dynamic DNS / Don't use SPF > > >SRS has a couple of problems, which make me assume that it's not going =
>to really get anywhere: > >1) If you implement SPF, then you have to rely on the fact that=20 >forwarding services of your recipients implemented SRS. The "mail from" rewrite done by srs on forwarded mails will be used as = is by any no 'srs' intermediate server on any next hops in the route to the = final server (that have not to be 'srs' too) >2) The from address gets mocked up. Making it not very "user = readable". NO, it's the SMTP "MAIL FROM" that is changed NEVER the 'From' field in = the mail itself The 'user' never see the 'Mail From' in any mua 'normal' views, but = only when wanting to view de complete headers and if the smtp servers added = some info about the real 'mail from' used in the smtp transaction. The 'From' is not derived from the SMTP "MAIL FROM", as the From is = allready in the mail header and written by the sender mua=20 >3) The from address SRS created would change from time to time (it=20 >includes a time stamp). So the same person sending me two=20 >mails, has two=20 >different addresses. Yes at smtp level, false at 'mua' level :) The final user see exactly the same address >4) The from address SRS created is meant to expire (otherwise=20 >abuse via=20 >such an address would be possible). So replying to that e-mail you=20 >received last week, won't work. Sure, you know all about SRS,=20 >so you're=20 >able to find out what the real address of the sender was. But=20 >will your=20 >mom be able to do so? False, as said, the mua use the From and Reply-to 'mail header' fields, = not the smtp "MAIL FROM" that they dont know nothing. So replying is ok and never change. > >Basically it comes down to this: >If you implement SPF, then you could assume that e-mails you send from = >servers that are "trusted" according to SPF and that don't get=20 >forwarded, are more likely to get through the spam filters. >But your SPF record is best to also allow mails from other servers=20 >simply because you never know if your recipient might be using=20 >forwarding. > >Sincerely, >Bart Mortelmans > > > Francis - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
