[Xorp-users] cannot ping one of the interfaces from an OSPF router after installing XORP
Liu, Xuan (UMKC-Student)
xuan.liu at mail.umkc.edu
Tue Aug 5 10:37:06 PDT 2014
Thank you Ben.
I just checked the ARP cache on the node that doesn't send ping reply properly. It turned out that the ARP cache kept updating all the time, sometimes it showed all the interfaces, and sometimes the entries to a particular IP was gone. Please refer my last post for details.
I have run the same topology on the Fedora nodes with XORP 1.7 before, and I didn't see this ping failures at that time. Does XORP help updating the ARP cache at the node?
Thanks,
Xuan
________________________________________
From: Ben Greear <greearb at candelatech.com>
Sent: Tuesday, August 5, 2014 11:08 AM
To: Liu, Xuan (UMKC-Student)
Subject: Re: [Xorp-users] cannot ping one of the interfaces from an OSPF router after installing XORP
On 08/05/2014 09:05 AM, Liu, Xuan (UMKC-Student) wrote:
> Here is the interfaces at rt-5
>
> root at rt-5> show ospf4 neighbor
> Address Interface State ID Pri Dead
> 192.168.13.1 eth1/eth1 Full 192.168.2.2 128 6
> 192.168.10.1 eth2/eth2 Full 192.168.6.2 128 9
> 192.168.3.1 eth3/eth3 Full 192.168.1.1 128 9
> 192.168.7.1 eth5/eth5 Full 192.168.1.2 128 7
>
>
> Looks fine to me, and I don't see any error in the log file.
Please keep replies on the list so that others may learn and help
answer.
I don't have time now to debug this, but you might try getting
the latest xorp code from git and see if that fixes the problem?
Thanks,
Ben
>
>
>
> Thanks,
>
> -- Xuan
>
>
> ________________________________________
> From: Ben Greear <greearb at candelatech.com>
> Sent: Tuesday, August 5, 2014 10:45 AM
> To: Liu, Xuan (UMKC-Student)
> Cc: xorp-users at xorp.org
> Subject: Re: [Xorp-users] cannot ping one of the interfaces from an OSPF router after installing XORP
>
> On 08/05/2014 08:32 AM, Liu, Xuan (UMKC-Student) wrote:
>> Hello,
>>
>>
>> I have came across this problem when I have configured a simple five-node network running OSPF protocol. The topology looks like
>>
>>
>> 1 --------------- 2
>>
>> / \ / \
>>
>> / \ / |
>>
>> 4 \ / 3
>>
>> | \ / |
>>
>> \ \ / /
>>
>> \ \ / /
>>
>> \------ 5 -----/
>>
>>
>> The link information is : rt1:eth4 -- rt2:eth1: 192.168.1.1 - 192.168.1.2
>>
>> rt2:eth4 -- rt3:eth3: 192.168.6.1 - 192.168.6.2
>>
>> rt3:eth2 -- rt5:eth2: 192.168.10.1 - 192.168.10.2
>>
>> rt5:eth1 -- rt4:eth3: 192.168.13.2 - 192.168.13.1
>>
>> rt4:eth2 -- rt1:eth2: 192.168.2.2 - 192.168.2.1
>>
>> rt1:eth3 -- rt5:eth3: 192.168.3.1 - 192.168.3.2
>>
>> rt2:eth2 -- rt5:eth5: 192.168.7.1 - 192.168.7.2
>>
>> All link has prefix 24.
>>
>>
>> Each node runs Ubuntu 12.04 OS, and I have installed XORP 1.8.5. For each node, I have configured it as an OSPF router. Most of the routing looks fine to me,
>> except for some interfaces. For example:
>>
>>
>> If I send ping request from rt1 to 192.168.7.2 (rt5), I got no response. The routing table at rt1, rt5 are like:
>>
>>
>> root at rt-1> show route table ipv4 unicast ospf
>> 192.168.6.0/24[ospf(110)/20]
>>> to 192.168.1.2 via eth4/eth4
>> 192.168.7.0/24[ospf(110)/20]
>>> to 192.168.1.2 via eth4/eth4
>> 192.168.10.0/24[ospf(110)/20]
>>> to 192.168.3.2 via eth3/eth3
>> 192.168.13.0/24[ospf(110)/20]
>>> to 192.168.2.2 via eth2/eth2
>>
>>
>>
>> root at rt-5> show route table ipv4 unicast ospf
>> 192.168.1.0/24[ospf(110)/20]
>>> to 192.168.3.1 via eth3/eth3
>> 192.168.2.0/24[ospf(110)/20]
>>> to 192.168.3.1 via eth3/eth3
>> 192.168.6.0/24[ospf(110)/20]
>>> to 192.168.10.1 via eth2/eth2
>>
>>
>> I ran tcpdump at rt1, rt2 and rt5 and found that
>>
>>
>> At rt-2 eth1:
>>
>> xuanliu at rt-2:~$ sudo tcpdump -i eth1 icmp -n
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
>> 11:22:58.797404 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 265, length 64
>> 11:22:59.805624 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 266, length 64
>> 11:23:00.813283 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 267, length 64
>> 11:23:01.821354 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 268, length 64
>>
>>
>> At rt-2 eth2:
>>
>> xuanliu at rt-2:~$ sudo tcpdump -i eth2 icmp -n
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
>> 11:24:08.347513 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 334, length 64
>> 11:24:09.355769 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 335, length 64
>> 11:24:10.363503 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 336, length 64
>>
>> At rt-5 eth5:
>> xuanliu at rt-5:/usr/local/xorp/sbin$ sudo tcpdump -i eth5 icmp -n
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on eth5, link-type EN10MB (Ethernet), capture size 65535 bytes
>> 11:24:52.122424 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 376, length 64
>> 11:24:53.130022 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 377, length 64
>> 11:24:54.138424 IP 192.168.1.1 > 192.168.7.2: ICMP echo request, id 11873, seq 378, length 64
>>
>> Based on the routing table at rt-5, the packet to 192.168.1.0 should be forwarded to link 192.168.3.0. So I checked the interface rt-5:eth3, and it showed nothing.
>>
>> xuanliu at rt-5:/usr/local/xorp/sbin$ sudo tcpdump -i eth3 icmp -n
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on eth3, link-type EN10MB (Ethernet), capture size 65535 bytes
>>
>>
>> Similarly, I couldn't ping rt-5:eth1 (192.168.13.2) from rt-1 neither. But I can ping 192.168.10.2, and 192.168.10.1, and the packets were forwarded from
>> rt-5:eth3(192.168.3.2) to rt-5:eth2(192.168.10.2)
>>
>>
>> Could you please provide any suggestion on how to troubleshooting this problem?
>
> Use xorpsh to print out the neighbors on rt-5, make sure your configuration interface
> is correct, look at the xorp logs to see if it shows any obvious errors, etc.
>
> Thanks,
> Ben
>
>>
>>
>> Thanks,
>>
>>
>> -- Xuan Liu
>>
>>
>> _______________________________________________
>> Xorp-users mailing list
>> Xorp-users at xorp.org
>> http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/xorp-users
>>
>
>
> --
> Ben Greear <greearb at candelatech.com>
> Candela Technologies Inc http://www.candelatech.com
>
--
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc http://www.candelatech.com
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