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Date: Tue, 16 Sep 2014 13:29:16 +0400 From: Andrey Dmitrov <andrey.dmitrov@...etlabs.ru> To: Neal Cardwell <ncardwell@...gle.com> CC: Netdev <netdev@...r.kernel.org>, "Alexandra N. Kossovsky" <Alexandra.Kossovsky@...etlabs.ru>, Konstantin Ushakov <kostik@...etlabs.ru> Subject: Re: TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised On 15/09/14 23:43, Neal Cardwell wrote: > On Mon, Sep 15, 2014 at 12:11 PM, Andrey Dmitrov > <andrey.dmitrov@...etlabs.ru> wrote: >> It is possible to create a lot of connections in the same manner which will be in FIN_WAIT1 state forever. > ... >> After ~10 minutes you will see 500 connections in the FIN_WAIT1 state on the host_A: >> netstat | grep FIN_WAIT1 | wc -l >> 500 > Thanks for the report. In your tests, have you ever seen the number of > such connections exceed net.ipv4.tcp_max_orphans? > > Can you set net.ipv4.tcp_max_orphans to a low value and verify that it > limits the number of such connections? AFAICT it should. I tried to set net.ipv4.tcp_max_orphans to 100, it limits the connections number. As I saw net.ipv4.tcp_max_orphans can be exceeded, but for a short time. Maximum connections number in FIN_WAIT1 state was 196, after that it was decreased rather fast to ~100. Thanks, Andrey -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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