Re: productivity?
2011-08-22 20:33:17
Sounds like a bug or poor windows socket implementation, not yours,
the other guy. :) #1 rule of thumb in Synchronization 101 is to not
depend on time. Inevitably it will bite you, maybe this year or even
never, but somehow it will rear its head. :) So if lowering TIME_WAIT
was one solution, it generally means there is some kind of sync design
problem and it might be a matter of issue a one time poke (Sleep(0))
to give other threads time, but immediately coming back. Sometimes it
can make all the difference. :)
Carl S. Gutekunst wrote:
Hector Santos wrote:
One issue not raised here: ephemeral port exhaustion. It's a rather
specialized problem, more of an issue for Windows folks than Linux,
and mostly an issue for routers, proxies, and similar devices that
tend to funnel a large volume of mail to smaller number of
destinations. But it's a real problem, one where reusing existing
client connections can provide a complete and permanent resolution.
The ephemeral port exhaustion exploit began with Microsoft DNS server
DoS attacks....
I'm talking about the normal operational condition where an SMTP sender
connects repeatedly to the same receiver. On platforms where the default
ephemeral port space is small (e.g., Windows Server 2003 and older BSD
kernels), the sender can exhaust the ephemeral ports. For those of us in
the filtering business, this is a constant nuisance.
The problem can be mitigated by increasing the number of ephemeral ports
(Vista defaults to the IANA recommend range), reducing TIME_WAIT, or
(tada!) reusing connections.
None of which has any relevance to any existing RFCs. But tuning
connection reuse might make for an interesting Informational doc or BCP.
<csg>
--
Sincerely
Hector Santos
http://www.santronics.com
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- Re: productivity?, (continued)
- RE: productivity?, Murray S. Kucherawy
- Re: productivity?, Hector Santos
- Re: productivity?, Paul Smith
- Re: productivity?, Hector Santos
- Improving Timeouts, Hector Santos
- Re: productivity?, Carl S. Gutekunst
- Re: productivity?, Hector Santos
- Re: productivity?, Carl S. Gutekunst
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Hector Santos <=
- Re: productivity?, Peter J. Holzer
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- Re: productivity? (was: Re: Mail Data termination), Sabahattin Gucukoglu
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