ietf-smtp
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Re: Mail Data termination

2011-08-18 18:49:34

Murray S. Kucherawy wrote:

The five-minute timeout is a SHOULD. If you're resource constrained, I would argue that issuing a 221 to the most idle open connection and closing it down so the resources can be re-used is just fine.

It has nothing to do with any system being constrained but one that can cause them to have new constraints, a higher TCO and need to scale up or out in order to satisfy what is guarantee to become new loading profile.

This should be done using an SMTP extension where a server can expose
server timeouts perhaps and willingness to allow a client to sit idle
redundantly and repeatedly.

Or it can simply impose an idle time that's more strict than what 4.5.3.2.7 of RFC5321 says, understanding that one needs to be pretty careful about doing so.

Whats going to happen is that implementors discovery might begin will change the timeout after a transaction is completed to 1 minute and zap CS clients out! I already have this Penciled in after seeing this was causing the increase SMTP session times from what was seconds to multiple minutes - TERRIBLE!

We spent a lot time and energy to optimized systems and the times out were designed to accommodate client/server handshaking processing and networking delay needs. It was not designed to allow a client to hold hostage communication channels chewing up CPU time and system availability needs.

No matter what limit is set on total receivers, if the modus operandi is the CS design, you will reach limit exhaustion far quicker. This can cause a higher potential for initial outbound failures on clients sending out mail, delays transactions, etc, etc.

--
Sincerely

Hector Santos
http://www.santronics.com


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