New warning message...

Barry Margolin barmar at alum.mit.edu
Mon Jul 22 16:22:51 UTC 2013


In article <mailman.881.1374508134.20661.bind-users at lists.isc.org>,
 Matus UHLAR - fantomas <uhlar at fantomas.sk> wrote:

> >>This was discussed here already, and imho this is anti-spf bullshit like
> >>all those "spf breaks forwarding" FUD. The SPF RR is already here and is
> >>preferred over TXT that is generik RR type, unlike SPF.
> 
> On 22.07.13 08:50, Barry S. Finkel wrote:
> >It is not Fear, Uncertainty, and Doubt that "SPF breaks forwarding".
> >SPF *DOES* break forwarding.
> 
> No, it does not. If a mail gets delivered to address, which is sending it
> further ("forwarding it"), the envelope sender has to be changed, because
> it's not the original sender who sends the another mail.  Forwarding without
> changing envelope address is already broken, it's just people don't care
> without SPF. 
> 
> >  I have a case I am researching right now
> >where forwarded mail is undeliverable due to SPF checking at the
> >new destination.
> 
> Rewrite the sender's address. You have more choices, SRS is one of them.

They're talking about auto-forwarding, not people resending a message 
they received. For instance, mail to barmar at alum.mit.edu is 
automatically forwarded by the alum.mit.edu server to my ISP email 
address. Many people also have vanity domains with auto-forwarding 
enabled like this.

Who should the sender be changed to?  AFAIK, it has never been standard 
practice to rewrite the sender when simply forwarding to an alias, which 
is what this is.

-- 
Barry Margolin
Arlington, MA


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