From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sven-Haegar Koch Subject: Re: routing bug? Date: Fri, 18 Nov 2011 13:48:03 +0100 (CET) Message-ID: References: <4EC648C9.8080405@uhulinux.hu> Mime-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323328-84160418-1321620483=:17023" Cc: Linux-Kernel-Mailinglist , =?ISO-8859-15?Q?Tam=E1si_J=E1nos?= , netdev@vger.kernel.org To: =?ISO-8859-15?Q?Pozs=E1r_Bal=E1zs?= Return-path: In-Reply-To: <4EC648C9.8080405@uhulinux.hu> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-84160418-1321620483=:17023 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Added netdev list to CC:, there you should have a higher chance of a usefull answer. On Fri, 18 Nov 2011, Pozs=E1r Bal=E1zs wrote: > Hi all, >=20 > I have been struggling with this not easily reproducible issue since a wh= ile. > I am using linux kernel v3.1.0, and sometimes routing to a few IP address= es > 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 trie= s to > gets its MAC address via ARP. >=20 > For example, now my current IP address is 172.16.1.104/24, the gateway is > 172.16.1.254: >=20 > |# 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 >=20 > # route -n > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use I= face > 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 e= th0 > 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 e= th0 > | >=20 > I can ping a few addresses, but not 172.16.0.59: >=20 > |# 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=3D1 ttl=3D64 time=3D0.383 ms >=20 > --- 172.16.1.254 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev =3D 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=3D1 ttl=3D63 time=3D5.54 ms >=20 > --- 172.16.0.1 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev =3D 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=3D1 ttl=3D62 time=3D7.92 ms >=20 > --- 172.16.0.2 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev =3D 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=3D1 Destination Host Unreachable >=20 > --- 172.16.0.59 ping statistics --- > 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms > | >=20 > When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was > sent: >=20 > |# tcpdump -n -i eth0|grep ARP > tcpdump: verbose output suppressed, use -v or -vv for full protocol decod= e > 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, lengt= h 28 > | >=20 > and /proc/net/arp has an incomplete entry for 172.16.0.59: >=20 > |# grep 172.16.0.59 /proc/net/arp >=20 > 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * e= th0 > | >=20 > Please note, that 172.16.0.59 /is/ accessible from this LAN from other > computers. >=20 >=20 > Does anyone have any idea of what's going on? Thanks, >=20 >=20 > Balazs Pozsar >=20 > ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/2= 92 >=20 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" i= n > 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/ >=20 >=20 --=20 Three may keep a secret, if two of them are dead. - Ben F. --8323328-84160418-1321620483=:17023--