On Tue, 2010-02-09 at 11:25 +0800, Ed Greshko wrote: > Bruno Wolff III wrote: > > On Tue, Feb 09, 2010 at 08:21:33 +0800, > > Ed Greshko <Ed.Greshko@xxxxxxxxxxx> wrote: > > > >> In the back of my mind, from a few years ago, I remember there an issue > >> with the linux TCP/IP stack and some "mis-configured" routers. I need > >> to get some coffee and hopefully my brain will get in gear.... > >> > > > > I believe that was ECN. (A way to signal congestion without throwing away > > packects.) > > > > There have also been problems with MTU discovery because people block ICMP > > packets indiscrimiantly. > > > > > That is starting to stir the synapse.... > > The problem is related to what is in the "syn, ack" packet coming from > 12.17.249.39. In the TCP Options it is sending "Window scale: 0 > (multiply by 1)". I think this is causing problems since later packets > have the TCP data segment being only 92 bytes from 12.17.249.39. > > While the same info is in the "syn, ack" the RHELv4 system seems to deal > with it OK and the TCP data segments from 12.17.249.39 are 1460 bytes. > > The "problem" can be fixed by.... > > echo 0 > /proc/sys/net/ipv4/tcp_window_scaling > > Now, while this fixes the problem for this site it may cause performance > issues with other sites. I don't know at this point and my head hurts. > :-) It is hurting since my RHELv4 system has tcp_window_scaling set to > 1 and it seems to deal with it. > > Note: Make sure you issue the "echo" above after some quite time. The > connection must first be rst (reset) before the sides will renegotiate > the TCP/IP settings. (That too caused me some grief.) > > I'll bugzilla it.... What became of the fix for this issue ? The reason I ask is because I'm now running Fedora 14 and a) I still have the problem and b) about every 3 days I have to edit the tcp_window_scaling file and reset the scaling entry to zero. Something over writes it back to true. Thanks ! -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
