Date: Fri, 20 May 2016 17:31:24 +0300 From: Vladimir Zakharov <zakharov.vv@gmail.com> To: Jan Bramkamp <crest@rlwinm.de> Cc: freebsd-current@freebsd.org Subject: Re: CURRENT: ipfw: problems with timeouts and worse network performance Message-ID: <20160520143124.GE2371@vzakharov> In-Reply-To: <0429473a-6bb6-70cb-05ca-fe0e83c173a0@rlwinm.de> References: <20160520140152.3ab6fe44@hermann> <20160520125401.GC2371@vzakharov> <38888426-4d91-56ed-9ab3-0d516b0b8d46@rlwinm.de> <20160520135109.GD2371@vzakharov> <0429473a-6bb6-70cb-05ca-fe0e83c173a0@rlwinm.de>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, May 20, 2016, Jan Bramkamp wrote: > On 20/05/16 15:51, Vladimir Zakharov wrote: > > On Fri, May 20, 2016, Jan Bramkamp wrote: > >> On 20/05/16 14:54, Vladimir Zakharov wrote: > >>> Hello > >>> > >>> On Fri, May 20, 2016, O. Hartmann wrote: > >>>> I reported earlier about broken pipes in ssh sessions to remote hosts, > >>>> which occur on an erratic basis. i'm investigating this problem now and > >>>> it seems that it is also ipfw-related, but I'm not sure. This problem > >>>> is present since a couple of weeks now. > >>> > >>> Maybe this could help... > >>> > >>> I've also experienced problems with broken pipes in ssh sessions some > >>> time ago. Setting in sysctl.conf > >>> > >>> net.inet.ip.fw.dyn_ack_lifetime=3600 > >>> > >>> fixed problem for me. I didn't experiment with the value though. So, > >>> possibly, changing default value (300s) to 1 hour is overkill :). > >> > >> By default the OpenSSH SSH client is configured to use TCP keepalives. > >> Those should produce enough packets at a short enough interval to keep > >> the dynamic IPFW state established. > >> > >> Does your traffic pass through libalias? > > I guess not. How can I be sure? > > Libalias is used by ipfw and the old userland natd to implement IPv4 > NAT. It requires unmodified access to all packets including their > headers. LRO and TSO coalesce packets to reduce save CPU time but the > process is loses some of the information required by libalias. Unless > your ruleset uses ipfw in-kernel NAT or diverts traffic to natd you > don't have to worry about libalias. > > Use `kldstat -v | grep libalias` to check for libalias in the running > kernel and `pgrep natd` to search for running natd instances. Surely, I do not use NAT (and libalias): root@vzakharov:~ # kldstat -v | grep libalias root@vzakharov:~ # pgrep natd I use GENERIC-NODEBUG kernel (r300138) with ipfw module. And 'workstation' firewall type. -- Regards, | "In theory there is no difference between theory Vladimir Zakharov | and practice. In practice there is."- Yogi Berra
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20160520143124.GE2371>