[CentOS-virt] Cannot get kvm guests to connect to network

James B. Byrne byrnejb at harte-lyne.ca
Fri Oct 12 09:16:07 EDT 2012

This cross-posted from the main Centos discussion list.

I installed a new CentOS-6.3 kvm guest on a recently provisioned kvm
host also running CentOS-6.3.  This guest will not connect to the
network and the host cannot connect to it via its public IP address. I
had previously installed a guest system on thst same kvm host using
the same ISO and that system connects to the network without problem.

I next created a third guest instance and this too does not connect
with either the kvm host or the gateway.

I have shutdown all the guests, restarted networking on the host and
restarted the gueests and the problem persists on the two most
recently added guests but does not happen on the first guest instance.

I have installed litterally dozens of kvm guests this past year and I
have never encountered this situation.  Has anyone else?  Does anyone
have any idea what might be going on?

ip addr
1: lo <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet scope host lo
    inet6 ::1/128 scope host
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP qlen 1000
    link/ether 52:54:00:a0:26:47 brd ff:ff:ff:ff:ff:ff
    inet brd scope global eth0
    inet6 fe80::5054:ff:fea0:2647/64 scope link
       vaslid_lft forever preferred_lft forever

ip route dev eth0  proto kernel  scope link  scr dev eth0  scope link  metric 1002
default via dev eth0

netstat -r
Kernel IP routing table
Destination    Gateway      Genmask        Flags  MSS Window  irtt Iface   *    U        0 0          0 eth0
link-local     *      U        0 0          0 eth0
default        UG       0 0          0 eth0

service iptables stop
.  .  .

PING ( 56(84) bytes of data.
>From icmp_seq=2 Destination Host Unreachable
>From icmp_seq=3 Destination Host Unreachable
>From icmp_seq=4 Destination Host Unreachable

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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
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