[CentOS] strange network problem
Juan Carlos Díaz Fernández
juan.carlos.diaz at ign-solutions.com
Fri Mar 5 15:01:04 UTC 2010
Are your netmask config Ok? Can you use wireshark to sniff traffic in the
middle LANCOM <->Wireshark/tcpdump<->Xenserver and send me a trace?
Juan Carlos Díaz Fernández
mailto: juan.carlos.diaz at ign-solutions.com
Innova Galicia Networks Solutions SL
Pazo de Feiras e Congresos de Lugo - Palomar s/n
27004 LUGO - Spain
callto: +34982284150 faxto: +34982284922
2010/3/5 Michael Schumacher <michael.schumacher at pamas.de>
> Nobody having an idea?
> > Hi,
> > 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
> > (xenserver1)
> > --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
> >>Server: 192.168.1.1
> >>Address: 192.168.1.1#53
> >>Non-authoritative answer:
> >>Name: www.centos.org
> >>Address: 22.214.171.124
> > but I cannot browse neither to "elinks http://www.centos.org" nor to
> > 126.96.36.199, 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
> >>10.1.1.0 * 255.255.255.0 U 0 0 0
> >>192.168.122.0 * 255.255.255.0 U 0 0 0
> >>169.254.0.0 * 255.255.0.0 U 0 0 0
> >>192.168.0.0 * 255.255.0.0 U 0 0 0
> >>default LANCOM_1751_1.p 0.0.0.0 UG 0 0 0
> > (eth1 is a drbd interface)
> >> [root at crmserver1 ~]# route
> >> Kernel IP routing table
> >> Destination Gateway Genmask Flags Metric Ref Use
> >> 169.254.0.0 * 255.255.0.0 U 0 0 0
> >> 192.168.0.0 * 255.255.0.0 U 0 0 0
> >> default LANCOM_1751_1.p 0.0.0.0 UG 0 0 0
> > Has anybody any clue where to look?
> best regards
> Michael Schumacher
> CentOS mailing list
> CentOS at centos.org
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