--- On Thu, 11/11/10, Mike Tancsa <m...@sentex.net> wrote:
> From: Mike Tancsa <m...@sentex.net> > Subject: Re: icmp packets on em larger than 1472 [SEC=UNCLASSIFIED] > To: freebsd-stable@freebsd.org > Date: Thursday, November 11, 2010, 10:01 PM > On 11/11/2010 12:26 AM, Kevin Oberman > wrote: > >> Date: Thu, 11 Nov 2010 13:01:26 +0800 > >> From: "Wilkinson, Alex" <alex.wilkin...@dsto.defence.gov.au> > >> Sender: owner-freebsd-sta...@freebsd.org > >> > >> > >> 0n Wed, Nov 10, 2010 at > 04:21:12AM -0800, Kirill Yelizarov wrote: > >> > >> >All my em cards > running 8.1 stable don't reply to icmp echo requests packets > larger than 1472 bytes. > >> > > >> >On stable 7.2 the same > hardware works as expected: > >> ># ping -s 1500 > 192.168.64.99 > >> >PING 192.168.64.99 > (192.168.64.99): 1500 data bytes > >> >1508 bytes from > 192.168.64.99: icmp_seq=0 ttl=63 time=1.249 ms > >> >1508 bytes from > 192.168.64.99: icmp_seq=1 ttl=63 time=1.158 ms > >> > > >> >Here is the dump on em > interface > >> >15:06:31.452043 IP > 192.168.66.65 > *****: ICMP echo request, id 28729, seq > 5, length 1480 > >> >15:06:31.452047 IP > 192.168.66.65 > ****: icmp > >> >15:06:31.452069 IP > **** > 192.168.66.65: ICMP echo reply, id 28729, seq 5, > length 1480 > >> >15:06:31.452071 IP *** > > 192.168.66.65: icmp > >> > > >> >Same ping from same > source (it's a 8.1 stable with fxp interface) to em card > running 8.1 stable > >> >#pciconf -lv > >> > >e...@pci0:3:4:0: > class=0x020000 card=0x10798086 chip=0x10798086 rev=0x03 > hdr=0x00 > >> > > vendor = 'Intel Corporation' > >> > > device = 'Dual Port Gigabit Ethernet > Controller (82546EB)' > >> > > class = network > >> > > subclass = ethernet > >> > > >> ># ping -s 1472 > 192.168.64.200 > >> >PING 192.168.64.200 > (192.168.64.200): 1472 data bytes > >> >1480 bytes from > 192.168.64.200: icmp_seq=0 ttl=63 time=0.848 ms > >> >^C > >> > > >> ># ping -s 1473 > 192.168.64.200 > >> >PING 192.168.64.200 > (192.168.64.200): 1473 data bytes > >> >^C > >> >--- 192.168.64.200 > ping statistics --- > >> >4 packets transmitted, > 0 packets received, 100.0% packet loss > >> > >> works fine for me: > >> > >> FreeBSD 8.1-STABLE #0 r213395 > >> > >> e...@pci0:0:25:0:class=0x020000 card=0x3035103c > chip=0x10de8086 rev=0x02 hdr=0x00 > >> vendor > = 'Intel Corporation' > >> device > = 'Intel Gigabit network connection > (82567LM-3 )' > >> class > = network > >> > subclass = ethernet > >> > >> #ping -s 1473 host > >> PING host(192.168.1.1): 1473 data bytes > >> 1481 bytes from 192.168.1.1: icmp_seq=0 ttl=253 > time=31.506 ms > >> 1481 bytes from 192.168.1.1: icmp_seq=1 ttl=253 > time=31.493 ms > >> 1481 bytes from 192.168.1.1: icmp_seq=2 ttl=253 > time=31.550 ms > >> ^C > > > > The reason the '-s 1500' worked was that the packets > were fragmented. If > > I add the '-D' option, '-s 1473' fails on v7 and v8. > Are the V8 systems > > where you see if failing without the '-D' on the same > network segment? > > If not, it is likely that an intervening device is > refusing to fragment > > the packet. (Some routers deliberately don't fragment > ICMP Echos Request > > packets.) > > > I am not sure I follow. If you do a > ping -s 1473 -D > on an interface that has the default MTU of 1500, it wont > work, as the > entire packet is going to be 1501 (note the data bytes) > > eg. > # ping -q -s 1472 -c 1 192.168.43.219 > PING 192.168.43.219 (192.168.43.219): 1472 data bytes > > --- 192.168.43.219 ping statistics --- > 1 packets transmitted, 1 packets received, 0.0% packet > loss > round-trip min/avg/max/stddev = 1.714/1.714/1.714/0.000 ms > on 192.168.43.219, I see > > and on .43.219, I see > > 0(ich10)# tcpdump -vvvni em2 icmp > tcpdump: listening on em2, link-type EN10MB (Ethernet), > capture size 96 > bytes > 13:49:17.564482 IP (tos 0x0, ttl 63, id 53656, offset 0, > flags [none], > proto ICMP (1), length 1500) > 192.168.42.11 > 192.168.43.219: ICMP echo > request, id 23315, seq 0, > length 1480 > 13:49:17.564499 IP (tos 0x0, ttl 64, id 14346, offset 0, > flags [none], > proto ICMP (1), length 1500) > 192.168.43.219 > 192.168.42.11: ICMP echo > reply, id 23315, seq 0, > length 1480 > > > Note the length is 1500 of the packet. > > That being said, if its failing on the em nic where you > dont specify the > -D flag on the ping, then there is a bug somewhere. > On certain em nics, > I found doing > ifconfig em0 -rxcsum > ifconfig em0 -txcsum > ifconfig em0 -tso > > works around a number of bugs > > ---Mike > Yes, i know it. This was the first thing i tried. Sorry, i didn't mention it. Kirill > > > _______________________________________________ > freebsd-stable@freebsd.org > mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org" > _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
