Date: Wed, 04 Mar 2015 02:41:07 +0100 From: "Michael Ross" <gmx@ross.cx> To: "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org>, "Rumen Telbizov" <telbizov@gmail.com> Subject: Re: Stale TIME_WAIT tcp connections Message-ID: <op.xux9mtx6g7njmm@michael-think.fritz.box> In-Reply-To: <CAENR%2B_U2H9Vf1xNjOGEsc0BuLhpTNL0iz81p5qDUxS_kdvfX5w@mail.gmail.com> References: <CAENR%2B_U2H9Vf1xNjOGEsc0BuLhpTNL0iz81p5qDUxS_kdvfX5w@mail.gmail.com>
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On Wed, 04 Mar 2015 01:36:18 +0100, Rumen Telbizov <telbizov@gmail.com> wrote: > Hello everyone, > > We have a server running 9.3-RELEASE which is exhibiting a high number of > TIME_WAIT tcp connections which are NOT being recycled. That is, netstat > reports them over and over again, no matter how long we wait for them to > be > flushed out. Currently this server has been out of rotation for a couple > of > hours and I still see the same tcp sockets there. Overall we have: > > # netstat -na | grep TIME_WAIT | wc -l > *30066* > > Tracking one particular TCP socket in TIME_WAIT proves that it stays > there > all the time. > > Another observation is that pfctl shows a very large number of state > entries, even after pfctl -F all, or disable/enable sequence. > > # pfctl -si > State Table Total Rate > current entries *59280* > > At the same time though: > > # pfctl -ss | wc -l > 18 > > After the problem was discovered we tried tweaking the following settings > without any luck: > > net.inet.tcp.fast_finwait2_recycle=1 > net.inet.tcp.finwait2_timeout=5000 > net.inet.tcp.maxtcptw=50000 > net.inet.tcp.msl=100 > > So it seems like this system is "stuck" and doesn't recycle those TCP > sockets. Again, the machine is out of rotation and not actively accepting > any traffic. I will keep it like that in case further investigation is > required. Please do let me know if there's anything else you'd like to > know > from the state of the machine or something I could try. > > Regards, Are you using any IPSEC? I observed something similar a while back, haven't checked again since i reported this. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=194690 Affected 9.2, too. Michael
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