[NCLUG] spam help

[Jake Edge]

Sean Reifschneider wrote:
> On Sun, Sep 10, 2006 at 04:21:29PM -0600, Jake Edge wrote:

> Except that it doesn't break forwarding.
> 
> It only breaks forwarding if a user forwards mail on to an server that
> enforces SPF, but they do not forward using the SPF-compatible forwarding
> (SRS).  In other words, the recipient has full control of this, and it only
> breaks in the case where the forward destination is using SPF.

I think it is fair to say that SPF breaks forwarding.  It may be that 
SRS provides a fix for that breakage, but in order for that to be the 
case, all MTAs that do any forwarding have to change to implement SRS.

Recipients absolutely do NOT have control over these things in general. 
  I cannot configure gmail (or yahoo or msn or ...) to start supporting 
SRS and given that SRS breaks 20+ years of tradition of not re-writing 
envelope senders, its adoption is unlikely to be universal (or even 
reasonably widespread) any time soon ...

Email users, by and large, do not have control of what their email 
admins choose to do ...

> Again, as I said before, this is only if *I* configure forwarding and do it
> improperly.  However, we don't tend to forward other domains, unless they
> are our own domains, which, you know, exist on this same server and so
> forwarding doesn't go through the SMTP-time SPF checks.

it is not only the mail that *you* forward that is affected ... all mail 
originating from your domains, bound for other people's inboxes can be 
affected by *your* SPF rules in ways that most email users have little 
or no control over ...

if you send me email to my gmail account and i have that forwarded 
elsewhere (say, yahoo) that does SPF checks, i may not be able to 
receive that mail ... you have in effect said that you don't want users 
to be able to forward email from you ... perhaps that is what you want ...

jake

-- 
Jake Edge - jake at edge2.net - http://www.edge2.net