Re[2]: [Declude.JunkMail] OT: Issues with Windows 2003 FTP service

[Sanford Whiteman]

 The  exact  source of the problem was a limit in threads in MS SMTP,
 which is something like 20 per processor (not sure if hyperthreading
 counts in this case). . .

This isn't an accurate claim. It sounds like you just haven't tried to
tune  MS  SMTP  appropriately  for load/resources/growth. That's fine,
since  MS  doesn't  push you too hard on this, but please do some more
lab work before deciding that MS SMTP is broken.

Look into the following values:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\InetInfo\Parameters\PoolThreadLimit

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SMTPSVC\Queuing\MaxPercentPoolThreads

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SMTPSVC\Queuing\AdditionalPoolThreadsPerProc

You  also  need to realize the differences between I/O completion port
architecture,  callbacks,  and  pure  multithreading. It's possible to
bottleneck anything, but that's an implementation problem with a given
event sink, not a problem with the overall framework.

 .  .  .  this  limitation  in  the  MS  SMTP  architecture  makes it
 inappropriate  for  any  full  scale  spam blocking solution such as
 Declude unless you have that application ride behind MS SMTP instead
 of being plugged into it. . . .

Sorry,  man,  but  that's FUD. I appreciate what you found with FTP in
your config, but let's not jump over the available data.

 One  other  note. I had previously used the Windows registry hack to
 enable  a  native  tarpitting  feature  in  MS  SMTP with even worse
 affects. The built-in tarpitting in MS SMTP will delay all 5xx error
 codes by the time that you set, and this included the 552 error used
 when messages are over the maximum size. The result of this terrible
 oversight  is  that  a fair number of servers will not recognize the
 delayed  552  error and will requeue the oversized messages over and
 over again, and that eats up a lot of bandwidth real, real quick.

Matt,  you  _know_  this  isn't cause and effect, since you and I both
looked   at  a  specific  server  _without_  tarpitting  enabled  that
exhibited  the  problem  with  oversize  messages.  There  may  be  an
additional  wrinkle  added by ttarpitting, but it's not the root cause
of the problem.

--Sandy



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

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Re[2]: [Declude.JunkMail] OT: Issues with Windows 2003 FTP service

[Sanford Whiteman]

 I am only passing on what I was told by Peter from VamSoft. There is
 a  whole thread on this where Peter confirmed the affect on FTP (but
 not  IIS)  in VamSoft's o.e.support newsgroup, which I see you found
 after sending this message.

Peter  is  very  smart  developer, but not a systems guy. You probably
noticed  our  back-and-forth  about  ORF's  64-bit support. During our
off-list  continuation,  I  was struck equally by his lack of facility
with  certain  common OS features (such as COM+) and yet the expertise
with  which  he  built  ORF  for scaleability and performance. I don't
expect him to do in-depth tweaking outside of his app (and I'm sure he
didn't touch these parameters here).

 I  personally  would  be  surprised  to  see a fixed (non-tweakable)
 thread  limit,  but  I  can't  make  a judgment without some form of
 verification  of your suggestion considering the guidance that I was
 given  (I'm not the programmer nor the expert).

Tweak  the  settings and open up a lot of sessions to your server; you
will  see  that the number of worker threads (as opposed to I/O ports)
that can be created rises accordingly.

 Regarding  the  MS SMTP tarpitting, you have to trust me on that, or
 at  least  test  it yourself before suggesting that I am wrong here.

I'm sure you _are_ seeing aggravated problems with tarpitting enabled.
Yet  it's  clear  that you've observed problems with oversize messages
_whether  or  not_  tarpitting  is  enabled, and you treated that fact
insufficiently, it seemed to me.

From  what you wrote, it sounds like running the sink that I wrote for
the  non-tarpitting  server would solve both problems. As you may have
noticed,  it  generates  a  DSN  that  does  not  include the original
message, just the subject line, the message size, and the size limit.

--Sandy



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

SpamAssassin plugs into Declude!
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Defuse Dictionary Attacks: Turn Exchange or IMail mailboxes into IMail Aliases!
  
http://www.imprimia.com/products/software/freeutils/exchange2aliases/download/release/
  
http://www.imprimia.com/products/software/freeutils/ldap2aliases/download/release/

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