incorrect spam setups cause spool messes on forwarders

Paul Vixie vixie at
Tue Dec 2 15:13:15 UTC 2003

> telling spammers 4xx or 5xx doesn't matter, they don't listen.

yes, but interestingly, every "smtp transport" (remote ip address who
connects to your tcp/25 service) who ignores 5XX (which you can tell
because they come back and try the same thing again over and over) is
either a spammer or the output side of a proxy (which might be hard
to detect).  so it turns out that ignoring 5XX is like sending up a
flare, "blackhole me!".
Paul Vixie

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