Re: [Exim] SMTP+SPF

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Author: Konrad Michels
Date:  
To: warren
CC: exim-users
Subject: Re: [Exim] SMTP+SPF
Hiya Warren!
Had a bit of a read through the SPF site, and an intial reading seems to
indicate a clever idea, I just wonder a bit about the implimentation
philosophy. Maybe I'm just reading it wrong, but from the looks of
things, if, like me, you're running exim on your laptop, and have
multiple e-mail accounts all over the show from which you collect mail
via POP3 or IMAP, you have a problem.

I have, for example, an domain, mail for which is handled by my machine
at home at the end of a cable connection which has a certain IP
address. Not being an ISP, I don't have my own DNS server, and make use
of EasyDNS for this domain. When I'm at work, either in the UK office
or in the Swiss office, I frequently send mail with reply-to etc
addresses set to my home domain. I also POP to that machine at home,
collect mail, and reply to it, which then automagically sets my reply-to
address as my home domain.

This would mean that I would have to get EasyDNS to publish SPF
information for my home domain which included all the possible IP
addresses from which mail from this domain could emanate? What happens
if I'm on business in, say, Copenhagen, making use of the Hotel's
internet connection, which means that mail will not be emanating from
the IP addresses listed in the SPF information?

I accept that this is a fairly isolated case, as not everyone roams with
a linux laptop, but I can see a similar problem emerging for contractors
working in different offices, using different mail addresses for
different aspects of their daily activity.

Or maybe I've just completely misunderstood the whole thing . . .

Later
Konrad


On Thu, 2003-07-31 at 09:51, warren@??? wrote:
> Hi All,
>
> I work colleague showed me a site called 'SMTP+SPF Sender Permitted From'
> (http://spf.pobox.com/). It's quite an interesting attempt to help aid the
> war on spam.
>
> It basically stops email forgery, so you can block spammers by sender
> domain. For more information please refer to the site as to exactly what it
> does and doesn't do, or to the draft RFC
> (http://spf.pobox.com/draft-mengwong-spf-01.txt).
>
> The author does mention that the ultimate goal would be to have native
> support built into an MTA. For now there have been some adopters and it
> appears that it will be supported by the upcoming SpamAssassin v2.70
> release.
>
> It would be interesting to hear your views on this and whether this should
> be something added to the Exim WishList or best left for products like
> SpamAssassin?
>
> Warren
>
>
> --
>
> ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim details at http://www.exim.org/ ##

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