backscatter by DSN: Service unavailable

Glenn Steen glenn.steen at
Thu Jan 24 13:59:23 GMT 2008

On 24/01/2008, hofu <hofu12 at> wrote:
> Hi all,
> our primary mailserver tags the spam and relays mail to other mailservers.
> Those sometimes have a different view of accepting messages
> and frequently reject spam mail
> (different view of DNS, different RFC inforcement). The primary server
> backscatters the tagged spam to falsified sender addresses.
> I am already rejecting spam from the subdomains mailservers with mailscanner
> upion reaxamining the mail
> but this happens as
> DSN: Service unavailable
> which I can't seem to intercept with mailscanner.
> Any chance to do this via watermarks or some such?
> Thanks
> hofu

Do you already do recipient verification (call ahead type of thing)?
Might solve a few of your problems:-).

-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se

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