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 <[EMAIL PROTECTED]> 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


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