spf-discuss
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Re: DMP vs SPF

2004-02-21 15:19:28

----- Original Message ----- 
From: "Meng Weng Wong" <mengwong(_at_)dumbo(_dot_)pobox(_dot_)com>
To: <spf-discuss(_at_)v2(_dot_)listbox(_dot_)com>
Sent: Saturday, February 21, 2004 10:54 AM
Subject: Re: [spf-discuss] DMP vs SPF


On Sat, Feb 21, 2004 at 07:16:30AM -0500, Hector Santos wrote:
|
| SPF itself has added atleast  1 to 3 seconds to the session time. But
the
| high delays are way too high with DMP to further ignore.
|

Hector, I really believe there is a serious problem in your DNS stack.

I had (and still have) some concern in this area too.  However,  it is all
intermittent so I am not sure.  More below.

If I read this correctly,

 - the SPF lookup takes 6.5 seconds to return
 - the DMP lookup takes 7.7 seconds
 - the dsbl lookup takes 2  seconds

Correct.


On my system, even with the overhead of loading Perl, then doing the
lookup, then parsing the result, SPF takes 0.056 wall-clock seconds.

Correct, same here.  That would be the first time lookup where I'm seeing
the delays.  Absolutely.  The following is someone here using the web based
tester 3 times and the lookup time result (no need to show the user info)

20040221 08:26:57 000134a6 sapspf     : pass (time:5281)
20040221 08:27:42 000134ab sapspf     : pass (time:0)
20040221 08:27:59 000134ac sapspf     : pass (time:0)

So it is can be very fast when cached.   But as I stated a few times,  most
spammer hits are random domains (valid or not), so your lookup is usually a
first time lookup.

What I have yet to fully comprehend or pin-point is whether there is a
problem with our network DNS setup as a primary server with with T1 provider
uunet as our uplink or this is a general non-authoritive" lookup issues
depending on the domain.   When I work from home on my DSL line (like now),
I see the same type of behavior.  It really all depends on the domain.
Again, I don't claim to be a DNS expect but I continue to research why this
is a issue.  I will have our network engineer check out the DNS server once
again come monday.

Question,  some TXT lookups have a non-zero TTL assign to it.   How do you
get a non-zero TTL assigned to a TXT record?

-- 
Hector Santos, Santronics Software, Inc.
http://www.santronics.com



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