> As per usual, total BS. :)

Since  you  don't  know  LDAP,  anything that doesn't say "simple text
file"  sounds  unfamiliar  and is thus waved off. Hey, SQL is scary to
anyone  who  only  uses Excel. Guess what? Databases purpose-built for
singleton  queries  are  faster  than  dumb  files. D'you really think
there's a conspiracy against ASCII?

It's like the "conf file vs. Registry" debate. Silly grudges that lead
people to arbitrarily decide that a new technology is "slower" or "not
faster"  --  as  opposed  to  "fragile"  or "opaque", which were valid
concerns -- and reveal their lack of experience with it. If you refuse
to  actually  test  a  technology,  c'mon,  stick with claims that are
intuitively  valid, as opposed to claims are at odds with common-sense
analysis of the two architectures.

> Why  would  any  MX  design  pass  "millions"  LDAP  queries for bad
> recipients  to  a  backend  server when those queries can be totally
> blocked at a correctly designed MX?

Nice  try with that glaring logical fallacy! You are trying to bait me
into accepting that "correct" design does not use LDAP. No go.

There  are  very,  very large mail server farms (_at least one_ of the
largest  in  the world) that use pure LDAP for validation because they
realize  that  it  is the fastest wire protocol for directory queries.
One  can  always  build  a  faster  in-memory  database  than  a given
networked  database...  but  text  files  are *not* faster, and clunky
export/import  is  just  ridiculous  to  me when higher performance is
available  within  a  standard  architecture  (LDAP  is  not always an
available  option;  we  are obvs. debating which is faster when _both_
are options, or else there's no debate).

Export/import  is  a  time-tested  kludge that is portable across many
different  directory/mailbox/MX vendors, and that's a good thing. Easy
to  implement,  absolutely. But you reveal your LDAP inexperience when
you endorse it for performance reasons. You cannot support that claim.
There  are  many  published LDAP benchmarks for huge directories. Test
the  same  number  of  concurrent lookups against an identically-sized
text  file. [I don't expect a retraction, since that's not your style;
but I know which technology will win, since I tested it extensively as
POC  when  writing LDAP plug-ins for IMail several years ago (and note
that  LDAP  daemons  are  faster  than  ever now, while text files are
running in place).]

At the risk of going over your head again with LDAP realities (I think
I  recited  all  of  this  in  a  post within the past 2 months): your
blanket use of the term "backend server" reveals that you really don't
know  how  directory servers work. Directory servers do not have to be
run on mailbox servers (although they certainly can be in environments
where  there  is no multi-purpose directory); nor are they monolithic,
as every LDAP server has robust replication capabilities; nor are they
CPU  or  network-hungry,  being  more conservative with both resources
when  compared  to  other networked databases and thus coexisting with
other services when necessary.

Nor  is  using  LDAP  even  mutually exclusive with having a recipient
database  that is "local" to an MX. I use OpenLDAP and ADAM replicated
databases  on  MXs.  The  MX runs its recip lookups using the standard
LDAP  API against loopback. Performance blows away text file traversal
for  the  same size userbase (obvs. at very small sizes the difference
is not observable).

Nor  does  using  LDAP  as  the  real-time repository preclude using a
local,  indexed in-memory (but *not* in-dumb-text-file) cache that has
a  non-LDAP  API.  As  I  said, you can always write something that is
faster  than  a  socket-based  database  (hey,  you  can hard-code and
compile your userbase into your SMTP daemon, although you'd still have
to have good indexing). Dumb text files are not that "something".

--Sandy



------------------------------------
Sanford Whiteman, Chief Technologist
Broadleaf Systems, a division of
Cypress Integrated Systems, Inc.
e-mail: [EMAIL PROTECTED]

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