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From: Sandy Drobic (no email)
Date: Sat Oct 01 2005 - 21:05:22 EDT
Noel Jones wrote:
> Likely the other site is using something that modifies the TCP stream,
> not by sending a junk command. Note this is happening when Len is
> trying to send mail (a sender address verification probe) not when
> receiving mail. They could be using QoS on a firewall to limit
> incoming smtp traffic to the equivalent of 1 char/second, or a tarpit
> program.
I don't remember any setting that would help in such a case. Postfix is
not aware of the network levels below smtp.
>> Perhaps smtpd_junk_command_limit, smtpd_noop_commands? The docs says
>> Postfix accepts by default 100 of these commands before it increases
>> the smtpd error count.
>
> The controls you suggest are effective when receiving mail, but not
> when sending mail, and postfix doesn't have any controls to drop slow
> connections (and it's not clear it should). Even the various
> smtp_*_timeout controls only work when the connection is stalled, won't
> help when it's very slow.
You're right. I'd better got to sleep now. (^-^)
Sandy
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