Walter Dnes wrote:
Maybe the only permanent answer is to...
- *not* deny that there may be *SOME* harm from DNSBLs
- but show that there is *MORE* harm in *NOT* using them
It doesn't seem to me that boosterism is really the right answer
though. DNSBL's are what they are. What would be nice to know as
an outsider is _what_ they are, how they roughly work, what their
upside is, and what their downside is. That way you can make the
risk/reward tradeoff which is invariably context sensitive.
- a DNSBL will send a 5XX reject to a legitimate sender's MTA, which
will notify the sender of the reject.
- a content-filter will bury the email in a "spam folder" with
thousands of real spam, where it'll probably never be found. The
sender will believe that the intended recipient has received the
message and ignored it, while the intended recipient will believe
that the sender hasn't sent the message.
That depends a whole lot on the receiving end's policy, doesn't it?
Spamassassin for example can use DNSBL's, the result of which is
effectively silent discard. And it would be a fairly trivial exercise
to make Spamassassin cause a 5xx to be generated for > 5.0 SA scores.
Mike
_______________________________________________
Asrg mailing list
Asrg(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/asrg