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Date:      Wed, 10 Nov 2010 23:49:56 -0800 (PST)
From:      Kirill Yelizarov <ykirill@yahoo.com>
To:        freebsd-stable@freebsd.org
Subject:   Re: icmp packets on em larger than 1472 [SEC=UNCLASSIFIED]
Message-ID:  <816869.17580.qm@web120510.mail.ne1.yahoo.com>
In-Reply-To: <20101111052656.21C0E1CC0E@ptavv.es.net>

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=0A=0A--- On Thu, 11/11/10, Kevin Oberman <oberman@es.net> wrote:=0A=0A> Fr=
om: Kevin Oberman <oberman@es.net>=0A> Subject: Re: icmp packets on em larg=
er than 1472 [SEC=3DUNCLASSIFIED]=0A> To: "Wilkinson, Alex" <alex.wilkinson=
@dsto.defence.gov.au>=0A> Cc: freebsd-stable@freebsd.org=0A> Date: Thursday=
, November 11, 2010, 8:26 AM=0A> > Date: Thu, 11 Nov 2010 13:01:26=0A> +080=
0=0A> > From: "Wilkinson, Alex" <alex.wilkinson@dsto.defence.gov.au>=0A> > =
Sender: owner-freebsd-stable@freebsd.org=0A> > =0A> > =0A> >=A0 =A0=A0=A00n=
 Wed, Nov 10, 2010 at=0A> 04:21:12AM -0800, Kirill Yelizarov wrote: =0A> > =
=0A> >=A0 =A0=A0=A0>All my em cards running=0A> 8.1 stable don't reply to i=
cmp echo requests packets larger=0A> than 1472 bytes.=0A> >=A0 =A0=A0=A0>=
=0A> >=A0 =A0=A0=A0>On stable 7.2 the same=0A> hardware works as expected:=
=0A> >=A0 =A0=A0=A0># ping -s 1500=0A> 192.168.64.99=0A> >=A0 =A0=A0=A0>PIN=
G 192.168.64.99=0A> (192.168.64.99): 1500 data bytes=0A> >=A0 =A0=A0=A0>150=
8 bytes from=0A> 192.168.64.99: icmp_seq=3D0 ttl=3D63 time=3D1.249 ms=0A> >=
=A0 =A0=A0=A0>1508 bytes from=0A> 192.168.64.99: icmp_seq=3D1 ttl=3D63 time=
=3D1.158 ms=0A> >=A0 =A0=A0=A0>=0A> >=A0 =A0=A0=A0>Here is the dump on em=
=0A> interface=0A> >=A0 =A0=A0=A0>15:06:31.452043 IP=0A> 192.168.66.65 > **=
***: ICMP echo request, id 28729, seq=0A> 5, length 1480=0A> >=A0 =A0=A0=A0=
>15:06:31.452047 IP=0A> 192.168.66.65 > ****: icmp=0A> >=A0 =A0=A0=A0>15:06=
:31.452069 IP ****=0A> > 192.168.66.65: ICMP echo reply, id 28729, seq 5, l=
ength=0A> 1480=0A> >=A0 =A0=A0=A0>15:06:31.452071 IP ***=0A> > 192.168.66.6=
5: icmp=0A> >=A0 =A0=A0=A0> =0A> >=A0 =A0=A0=A0>Same ping from same source=
=0A> (it's a 8.1 stable with fxp interface) to em card running=0A> 8.1 stab=
le=0A> >=A0 =A0=A0=A0>#pciconf -lv=0A> >=A0=0A> =A0=A0=A0>em0@pci0:3:4:0:=
=A0=A0=A0=0A> class=3D0x020000 card=3D0x10798086 chip=3D0x10798086 rev=3D0x=
03=0A> hdr=3D0x00=0A> >=A0 =A0=A0=A0>=A0 =A0 vendor=A0=0A> =A0=A0=A0=3D 'In=
tel Corporation'=0A> >=A0 =A0=A0=A0>=A0 =A0 device=A0=0A> =A0=A0=A0=3D 'Dua=
l Port Gigabit Ethernet Controller=0A> (82546EB)'=0A> >=A0 =A0=A0=A0>=A0 =
=A0 class=A0=0A> =A0 =A0 =3D network=0A> >=A0 =A0=A0=A0>=A0 =A0=0A> subclas=
s=A0=A0=A0=3D ethernet=0A> >=A0 =A0=A0=A0>=0A> >=A0 =A0=A0=A0># ping -s 147=
2=0A> 192.168.64.200=0A> >=A0 =A0=A0=A0>PING 192.168.64.200=0A> (192.168.64=
.200): 1472 data bytes=0A> >=A0 =A0=A0=A0>1480 bytes from=0A> 192.168.64.20=
0: icmp_seq=3D0 ttl=3D63 time=3D0.848 ms=0A> >=A0 =A0=A0=A0>^C=0A> >=A0 =A0=
=A0=A0>=0A> >=A0 =A0=A0=A0># ping -s 1473=0A> 192.168.64.200=0A> >=A0 =A0=
=A0=A0>PING 192.168.64.200=0A> (192.168.64.200): 1473 data bytes=0A> >=A0 =
=A0=A0=A0>^C=0A> >=A0 =A0=A0=A0>--- 192.168.64.200 ping=0A> statistics ---=
=0A> >=A0 =A0=A0=A0>4 packets transmitted, 0=0A> packets received, 100.0% p=
acket loss=0A> > =0A> > works fine for me:=0A> > =0A> > FreeBSD 8.1-STABLE =
#0 r213395=0A> > =0A> > em0@pci0:0:25:0:class=3D0x020000 card=3D0x3035103c=
=0A> chip=3D0x10de8086 rev=3D0x02 hdr=3D0x00=0A> >=A0 =A0=A0=A0vendor=A0=0A=
> =A0=A0=A0=3D 'Intel Corporation'=0A> >=A0 =A0=A0=A0device=A0=0A> =A0=A0=
=A0=3D 'Intel Gigabit network connection=0A> (82567LM-3 )'=0A> >=A0 =A0=A0=
=A0class=A0 =A0 =A0 =3D=0A> network=0A> >=A0 =A0=A0=A0subclass=A0=A0=A0=3D=
=0A> ethernet=0A> > =0A> > #ping -s 1473 host=0A> > PING host(192.168.1.1):=
 1473 data bytes=0A> > 1481 bytes from 192.168.1.1: icmp_seq=3D0 ttl=3D253=
=0A> time=3D31.506 ms=0A> > 1481 bytes from 192.168.1.1: icmp_seq=3D1 ttl=
=3D253=0A> time=3D31.493 ms=0A> > 1481 bytes from 192.168.1.1: icmp_seq=3D2=
 ttl=3D253=0A> time=3D31.550 ms=0A> > ^C=0A> =0A> The reason the '-s 1500' =
worked was that the packets were=0A> fragmented. If=0A> I add the '-D' opti=
on, '-s 1473' fails on v7 and v8. Are=0A> the V8 systems=0A> where you see =
if failing without the '-D' on the same=0A> network segment?=0A> If not, it=
 is likely that an intervening device is refusing=0A> to fragment=0A> the p=
acket. (Some routers deliberately don't fragment ICMP=0A> Echos Request=0A>=
 packets.) =0A=0AIf i set -D -s 1473 sender side refuses to ping and that i=
s correct. All mentioned above machines are behind the same router and swit=
ch. Same hardware running v7 is working while v8 is not. And i never saw su=
ch problems before.  Also correct me if i'm wrong but the dump shows that t=
he packet arrived. I'll try driver from head and will post here results. =
=0A=0AKirill=0A> -- =0A> R. Kevin Oberman, Network Engineer=0A> Energy Scie=
nces Network (ESnet)=0A> Ernest O. Lawrence Berkeley National Laboratory (B=
erkeley=0A> Lab)=0A> E-mail: oberman@es.net=A0=A0=A0=0A> =A0=A0=A0 =A0=A0=
=A0 Phone: +1 510=0A> 486-8634=0A> Key fingerprint:059B 2DDF 031C 9BA3 14A4=
=A0 EADA 927D=0A> EBB3 987B 3751=0A> ______________________________________=
_________=0A> freebsd-stable@freebsd.org=0A> mailing list=0A> http://lists.=
freebsd.org/mailman/listinfo/freebsd-stable=0A> To unsubscribe, send any ma=
il to "freebsd-stable-unsubscribe@freebsd.org"=0A> =0A=0A=0A      



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