Re: [exim] Exim and SPF

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Autor: Ian Eiloart
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A: Marc Perkel, exim-users
Assumpte: Re: [exim] Exim and SPF


--On 10 December 2009 09:17:21 -0800 Marc Perkel <marc@???> wrote:

> Is anyone using SPF in Exim? I'm still trying to figure out a use for it.


If you do sender address whitelisting, you should insist on an SPF pass
first. 60% of the email that we deliver today has an SPF pass. Most of the
rest is from domains without SPF records.

If you see an SPF pass for a domain that you trust, then you should use SRS
before forwarding. Otherwise, you might prefer not to risk tarnishing your
domain reputation.

> 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 guess you should reject mail from domains with +all. I'm not sure if
Exim's SPF facilities do that.

> 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?




--
Ian Eiloart
IT Services, University of Sussex
01273-873148 x3148
For new support requests, see http://www.sussex.ac.uk/its/help/