[Mimedefang] Re: Too Many Open Files (again?)

[Lucas Albers]

I lowered the timeouts on my system, because of dirty slow evil smtp
servers that would just not close the connection, or resolve ip addresses.
Before I did this I usually had 10-20 open stalled connections at a time.

Has not caused ANY problems on ANY connections since I implemented it 6
months ago.

Sample sendmail entries:

dnl this has never caused problems on mail delivery, it just removes
troublesome
dnl mailers (spammers that won't resolve ip or similar.)
define(`confTO_COMMAND',240s)dnl

dnl timeout on initial outgoing connection
define(`TimoutIconnect=30s')dnl

dnl other items I have configured.
define(`ConnectionRateThrottle',8')dnl limit number of connections per
second that are permitted.
define(`confBAD_RCPT_THROTTLE',`2')dnl limit spammers from trolling for
users on the system, reject all mail after 2 bad recipients.


> * Matlock , Justin <JMatlock at innotrac.com>
>> What ended up happening, is these super-slow connections were opening
>> tons of sockets, but those sockets were never closing.  Sendmail never
>> timed out, because characters were being sent, just *very* slowly.
>
> Sendmail has some very conservative timeout values such as Timeout.rcpt,
> Timeout.datablock, and Timeout.datafinal being set to 1h by default.
> However, I have not experimented with lowering any of them to
> potentially avoid such problems as you are seeing.  With lower timeouts,
> one would expect to see temporary failures and resend attempts rather
> than slow starvation of resources?
>
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