On Wed, 10 Mar 2004, Jeff Makey wrote:
> Dave Funk wrote:
> > 553 5.1.8 <[EMAIL PROTECTED]>... Domain of sender address [EMAIL
> > PROTECTED] does not exist
> >
> >You do a DNS resolvability check on each message that somebody tries to
> >hand you, which is dependent upon an arbitratry remote DNS server.
> >Based upon the results of that DNS lookup, you do reject mail.
> >Thus I could argue that you do use DNSBL lists.
>
> DNS blacklist maintainers are self-appointed and have varying
> reputations that may be difficult to ascertain reliably. Few people
> would recommend the risky idea of using a poorly-chosen DNS-based
> blacklist.
Agreed 100%. If you had read the rest of my post you would note that I
talked about issues of trust and "do due diligence" when deciding what
sources of information to use. This applies to DNS or other forms of
remote information such as DCC, Razor, BondedSender, etc.
ANY badly maintained DNS system is a disservice to those affected by it.
The main purpose of that post was to point out to Glenn Little
that he was doing DNS lookups on every message arriving at his system
and making accept/reject decisions upon that information.
That was in answer to his previous post questioning the sense of doing
DNSBL lookups PURELY on the grounds of performance and reliability
concerns.
> Confirming that a sending domain really exists is a form of whitelist
> query to the properly delegated authority for the domain. This
> function is very different from DNSBL queries, and it would be better
> if you didn't try to mislead people into thinking that they are
> morally equivalent just because they both use the DNS.
>
> :: Jeff Makey
> [EMAIL PROTECTED]
I am not trying to get into a holy war here, I was trying to point
out the technical feasability of using DNS to get information about
a message for filtering purposes (either for accept/reject decisions
or SA scoring).
--
Dave Funk University of Iowa
<dbfunk (at) engineering.uiowa.edu> College of Engineering
319/335-5751 FAX: 319/384-0549 1256 Seamans Center
Sys_admin/Postmaster/cell_admin Iowa City, IA 52242-1527
#include <std_disclaimer.h>
Better is not better, 'standard' is better. B{
