On Sun, Jul 25, 2004 at 06:06:04PM +0200, you [Henrik Nordstrom] wrote: > On Sun, 25 Jul 2004, Ville Herva wrote: > > > > May be a MTU blackhole in the path from the server to you. > > > > Sorry for my cluelessness here, but does that explain the oddness in the > > tcpdump David S. Miller pointed out? > > At least the beginning of the trace. One or two of the packets (the first > data packets) from the server to you have gone missing. Ok, I see. > > It seems a mere > > ifconfig eth0 <ip> netmask <nm> mtu 1458 up > > was enough to make the problem go away (instead of the default MTU=1500). > > This also adjusts the MSS but in a more intrusive manner. Ok, I see. > > It could just be that the must-fragment icmp packets do not get back to > > my machine (the problem appeared few weeks ago when my ISP changed the > > connection from lease physical cable to their own cable - but it could > > of course be also be a misconfiguration on my side.) > > The problem is almost certainly in the other direction, must-fragment icmp > packets in the direction from you to the server gets lost. This is what > you can test most easily by playing with the MSS option, or in some > limited cases by tuning the MTU. Ok, I see. I contacted my ISP, and I think there is a remote chance they'll look at the problem. I won't be holding my breath, though. > > I don't know if these explain the oddness in the tcpdump, though. > > It does not. Weird. Thank you very much for your insights! - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
