--On 10 December 2009 09:30:38 -0800 Dan_Mitton@??? wrote:
> Yes, we use SPF in Exim here. Basically, we just reject anything that
> gets an SPF fail. We have however also had to create a 'white list' of
> external senders that send on our behalf to us, using our domain names.
> We are rejecting several hundred thousand messages a week, about 50%.
> Most of the rejects are spam using our domain names as the supposed
> sender.
Yes, that's an interesting case. It's one that we implemented years ago,
but without SPF, and with a simple (easily forged) signature to allow
messages to be forwarded back to our site. Our "internal" email is
virtually spam free, but that fact relies on the rarity with which spammers
seem to use different "From" and return path addresses. It's been
successful for many years now, but I've always expected to have to replace
it with SPF and DKIM.
> Dan
>
>
>
> Sent by: exim-users-bounces@???
> To: exim-users@???
> cc: (bcc: Dan Mitton/YD/RWDOE)
> Subject: [exim] Exim and SPF
> LSN: Not Relevant - Not Privileged
> User Filed as: Excl/AdminMgmt-14-4/QA:N/A
>
> Is anyone using SPF in Exim? I'm still trying to figure out a use for it.
>
> One thing I thought of is a way of determining who is forwarding email.
> If SPF doesn't match but the email is clearly not spam then the sending
> host might be forwarding email and might make it on a list of legit
> forwarders.
>
> Might be a way of detecting spammers who use SPF by the hosts they
> reference in their SPF record.
>
> I might send out notices to those with too restrictive of SPF that their
> email might bounce if the recipient uses hosted spam filtering.
>
> What are the rest of you doing with SPF?
>
>
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--
Ian Eiloart
IT Services, University of Sussex
01273-873148 x3148
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