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Re: [Asrg] Fwd: Returned mail: see transcript for details

2003-04-01 07:47:03
In <200304010403(_dot_)h3143aeW023620(_at_)calcite(_dot_)rhyolite(_dot_)com> 
Vernon Schryver <vjs(_at_)calcite(_dot_)rhyolite(_dot_)com> writes:

From: wayne <wayne(_at_)midwestcs(_dot_)com>

Ah.  What I meant is that I can check to see if someone is in the
SPEWS DNSBL, but I can't see if a given email will be rejected as spam
by a given content filter. 

Again, given an SMTP server and a test message, simply send the test
message to an invalid mailbox at that server.  If the bounce you get
from the remote server or your own SMTP client says "user unknown,"
then chances that are the remote SMTP server will not have filtered
the same message if sent to a valid address.

Uh, I don't see how you can come to that conclusion.  Most MTAs will
reject the invalid mailbox at the SMTP RCTP TO time and the actual
mail message won't even be delivered the receiving MTA.



                                 The same applies to DNS blacklists,
because MTAs can and do lie about how they use DNS blacklists [...]

The point I was making is that it is easier for people to complain
about DNSBLs because they are easier to publicly show that they are
listed on the BL.  This means that the number of public rants against
DNSBLs is misleading compared with other anti-spam systems that aren't
as transparent.



-wayne

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