tweaking max sessions / scaling

Mike Tancsa mike at
Wed Sep 27 05:17:15 AEST 2017

Other than cranking up logging to debug2, is there a way to better tune
logging on a server to see if I am running into max sessions ? On
FreeBSD RELENG11 I am periodically seeing connections being refused-
3way handshake not completing or completing and then FINs.

Typically, I have a hundred or so connections at one time, but they can
bounce up to a few hundred on occasion.  Without leaving the server at
debug2 logging level, is there a way to find out if I am hitting
application limits vs OS limits ?

Also, are there any guides out there on tuning an sshd (sftp actually)
server to handle a large number of concurrent sessions ?

Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at
Providing Internet services since 1994
Cambridge, Ontario Canada

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