Messages in this thread |  | | | Date | Fri, 18 Nov 2011 13:48:03 +0100 (CET) | | From | Sven-Haegar Koch <> | | Subject | Re: routing bug? |
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Added netdev list to CC:, there you should have a higher chance of a usefull answer.
On Fri, 18 Nov 2011, Pozsár Balázs wrote:
> Hi all, > > I have been struggling with this not easily reproducible issue since a while. > I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses > does not work. What seems to happen is that instead of sending the packet to > the gateway, the kernel treats the destination address as local, and tries to > gets its MAC address via ARP. > > For example, now my current IP address is 172.16.1.104/24, the gateway is > 172.16.1.254: > > |# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC > inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 > TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) > Interrupt:17 > > # route -n > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use Iface > 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 > 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 > | > > I can ping a few addresses, but not 172.16.0.59: > > |# ping -c1 172.16.1.254 > PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. > 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms > > --- 172.16.1.254 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms > root@pozsybook:~# ping -c1 172.16.0.1 > PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. > 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms > > --- 172.16.0.1 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms > root@pozsybook:~# ping -c1 172.16.0.2 > PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. > 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms > > --- 172.16.0.2 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms > root@pozsybook:~# ping -c1 172.16.0.59 > PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. > From 172.16.1.104 icmp_seq=1 Destination Host Unreachable > > --- 172.16.0.59 ping statistics --- > 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms > | > > When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was > sent: > > |# tcpdump -n -i eth0|grep ARP > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode > listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes > 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 > | > > and /proc/net/arp has an incomplete entry for 172.16.0.59: > > |# grep 172.16.0.59 /proc/net/arp > > 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 > | > > Please note, that 172.16.0.59 /is/ accessible from this LAN from other > computers. > > > Does anyone have any idea of what's going on? Thanks, > > > Balazs Pozsar > > ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >
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