[CentOS] strange network problem
michael.schumacher at pamas.de
Fri Mar 5 13:00:41 UTC 2010
Nobody having an idea?
> I am trying to fix a problem I have for about a week now.
> The environment is:
> --several independent servers with Centos5.4 on the latest patchlevel
> (example will be server2) All of them are working properly.
> --a machine with Xen installed to host some virtual machines
> --domu servers on xenserver1 (crmserver1, winserver1)
> The whole network is connected with a Lancom router to a DSL line.
> Some days ago I noticed that server2 was updated properly, but
> xenserver1, crmserver1 and winserver were not updating the OS
> properly. They seemed to be cut off the internet. I can ping from all
> to all servers internally, I can ssh from all to all servers
> internally and I can browse the Internet from server2 successfully
> (using IP-numbers and hostnames), but xenserver1 and its domu clients
> could not connect to the internet. I checked the firewalls on
> xenserver, and crmserver1. They seemed to be OK and stopping them with
> "etc/init.d/iptables stop" didn't solve the problem.
> I can resolve hostnames:
>>[root at xenserver1 ~]# nslookup www.centos.org
> but I cannot browse neither to "elinks http://www.centos.org" nor to
> 220.127.116.11, however, I can ping www.centos.org successfully.
> the network routes seem to be OK :
>>[root at xenserver1 ~]# route
>>Kernel IP routing table
>>Destination Gateway Genmask Flags Metric Ref Use Iface
>>10.1.1.0 * 255.255.255.0 U 0 0 0 eth1
>>192.168.122.0 * 255.255.255.0 U 0 0 0 virbr0
>>169.254.0.0 * 255.255.0.0 U 0 0 0 eth0
>>192.168.0.0 * 255.255.0.0 U 0 0 0 eth0
>>default LANCOM_1751_1.p 0.0.0.0 UG 0 0 0 eth0
> (eth1 is a drbd interface)
>> [root at crmserver1 ~]# route
>> Kernel IP routing table
>> Destination Gateway Genmask Flags Metric Ref Use Iface
>> 169.254.0.0 * 255.255.0.0 U 0 0 0 eth0
>> 192.168.0.0 * 255.255.0.0 U 0 0 0 eth0
>> default LANCOM_1751_1.p 0.0.0.0 UG 0 0 0 eth0
> Has anybody any clue where to look?
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