Sorry to double post but I should have included this info. mtu == 1500 for the following ping -s 5000 172.17.187.220 tcpdump run on 172.17.187.220 tcpdump -n -i eth0 host 172.17.187.221 10:17:53.618060 IP 172.17.187.221 > 172.17.187.220: icmp 10:17:53.618062 IP 172.17.187.221 > 172.17.187.220: icmp 10:17:53.618065 IP 172.17.187.221 > 172.17.187.220: icmp 10:17:53.618095 IP 172.17.187.220 > 172.17.187.221: icmp 1480: echo reply seq 4 10:17:53.618099 IP 172.17.187.220 > 172.17.187.221: icmp 10:17:53.618100 IP 172.17.187.220 > 172.17.187.221: icmp now I lower the mtu ifconfig eth0 mtu 1492 ping -s 5000 172.17.187.220 tcpdump run on 172.17.187.220 tcpdump -n -i eth0 host 172.17.187.221 10:20:03.185397 IP 172.17.187.221 > 172.17.187.220: icmp 10:20:03.185400 IP 172.17.187.221 > 172.17.187.220: icmp 10:20:03.185402 IP 172.17.187.221 > 172.17.187.220: icmp 10:20:03.185433 IP 172.17.187.220 > 172.17.187.221: icmp 1480: echo reply seq 4 10:20:03.185436 IP 172.17.187.220 > 172.17.187.221: icmp 10:20:03.185438 IP 172.17.187.220 > 172.17.187.221: icmp 10:20:03.185440 IP 172.17.187.220 > 172.17.187.221: icmp So as you can see they are the same however the reply never comes back as proved by this tcpdump. tcpdump run on 172.17.187.221 tcpdump -n -i eth0 host 172.17.187.22 10:24:51.105366 IP 172.17.187.221 > 172.17.187.220: icmp 10:24:51.105369 IP 172.17.187.221 > 172.17.187.220: icmp 10:24:51.105371 IP 172.17.187.221 > 172.17.187.220: icmp 10:24:51.105652 IP 172.17.187.220 > 172.17.187.221: icmp 10:24:52.105450 IP 172.17.187.221 > 172.17.187.220: ICMP echo request, id 42519, seq 3, length 1472 10:24:52.105455 IP 172.17.187.221 > 172.17.187.220: icmp 10:24:52.105456 IP 172.17.187.221 > 172.17.187.220: icmp 10:24:52.105458 IP 172.17.187.221 > 172.17.187.220: icmp 10:24:52.105669 IP 172.17.187.220 > 172.17.187.221: icmp 10:24:53.105545 IP 172.17.187.221 > 172.17.187.220: ICMP echo request, id 42519, seq 4, length 1472 On 2/6/07, Brett Curtis wrote: > > have tried everything possible short of testing a different network card > because I do not have one. I have delt with IMB support but since I run > gentoo they are not much if any help at all. I compiled the drivers they > provide with the same results. I tried booting from gentoo live disk.. I > am > running out of ideas. I have tried doing this on different network > switches > differnt cables... and still nothing. > > I can not lower the mtu on *any* on my Broadcom Corporation NetXtreme > nics. > I > have 5 of these boxes! Same results on all. > > my test is this: > > ping -s 5000 somehost.inmy.lan > > works as expected. > > ifconfig eth0 mtu 1492 > ping -s 5000 somehost.inmy.lan > > nothing.. and of course I set my mtu back to 1500 everything works fine. > > I have done this same test with machines with different nics and > everything > works. > > I am building 2.6.20 now in hopes it may fix something. > > Any ideas? > > Thanks > > -- > > Created with VIM & mutt. > > Our comedies are not to be laughed at. -Samuel Goldwyn > >