Re: smtp+spf and dynamic ip?

lee wrote:
> Decided to upgrade my postfix and put a mailserver back online with the
> latest and greatest. It looks like SPF has stuck around. Couple of
> questions tho:
>
> 1. Am I correct in reading between the lines that SPF and dynamic ip
> updaters won't work and play well together?
>
> 2. Even tho SPF has stuck around, doesn't mean it's caught on. Has it
> caught on?
>
> 3. Has it reached a critical mass yet?
>
> Thanks,
>

I was going to write this out but I found a post that explains it better
than I could. Taken from the qmail mailing list:

http://marc.theaimsgroup.com/?l=qmail&m=109867517302615&w=2

SPF breaks forwarding (check out the FAQ on
http://spf.pobox.com/faq.html, it says so right there), totally and
completely.

The solution they put forward it to change from forwarding to
re-mailing, essentially, making the forwarding machine take
responsibility for the mail, and to modify the mail before sending it on
to the address the mail is being remailed to (aka SRS). This, however,
makes it reasonably easy for spammers to send messages to your box
pretending that this message I'm sending is a bounce message (even
though it isn't) and tricking your box into sending it onward. In order
to prevent abuse, requires the forwarding machine to keep a potentially
unbounded database of messages it has forwarded (a rather un-attractive
thing for a server that, for example, processes a few million messages
or more a day) so that it knows it only has to decode-and-forward
bounces from messages that it did actually send.
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Received on Wed Apr 20 15:02:31 2005