Ping from openvz VM is not available

Question

This openvz box was working properly few weeks ago, and now it can't ping the outside world.

I'm not expert on networking, and I thought the initial working setup will last longer.

Another stange stuff is that web services of this VM are available from outside.

Ping network interface:

vz:/# ping 88.191.118.xxx
PING 88.191.118.xxx (88.191.118.xxx) 56(84) bytes of data.
64 bytes from 88.191.118.xxx: icmp_req=1 ttl=64 time=0.048 ms
64 bytes from 88.191.118.xxx: icmp_req=2 ttl=64 time=0.043 ms
--- 88.191.118.xxx ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.043/0.045/0.048/0.007 ms

Ping google:

vz:/# ping 74.125.230.83
PING 74.125.230.83 (74.125.230.83) 56(84) bytes of data.
--- 74.125.230.83 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3023ms

ifconfig:

vz:/# ifconfig
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:59 errors:0 dropped:0 overruns:0 frame:0
          TX packets:59 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:5507 (5.3 KiB)  TX bytes:5507 (5.3 KiB)

venet0    Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          inet addr:127.0.0.1  P-t-P:127.0.0.1  Bcast:0.0.0.0  Mask:255.255.255.255
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1
          RX packets:89 errors:0 dropped:0 overruns:0 frame:0
          TX packets:584 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:20938 (20.4 KiB)  TX bytes:395767 (386.4 KiB)

venet0:0  Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          inet addr:192.168.23.101  P-t-P:192.168.23.101  Bcast:0.0.0.0  Mask:255.255.255.255
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1

Routes:

vz:/# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.0.2.1       0.0.0.0         255.255.255.255 UH    0      0        0 venet0
0.0.0.0         192.0.2.1       0.0.0.0         UG    0      0        0 venet0

iptable on host:

iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
fail2ban-ssh  tcp  --  anywhere             anywhere            multiport dports ssh 

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain fail2ban-ssh (1 references)
target     prot opt source               destination         
RETURN     all  --  anywhere             anywhere 

Answer 1

Well, as we can see here, the network config looks strange

First the routes -

• There is no default route that can be reached.
• The two routes appears to use an interface that points to itself (127.0.0.1)

Then the interfaces

• Do you really want to point venet0 to itself?
• The broadcast/netmask appears to be weird for venet0:0

Maybe you could... draw a network diagram and let us help...

Answer 2

Solved: the box was rebooted 2 weeks ago, and the iptables script was not launched.

Current firewall.sh script:

sd-20628:~# more firewall.sh 
#!/bin/bash
IPTABLES='/sbin/iptables';

VZ101_WEB="192.168.23.101";

LAN="192.168.23.0/24";

WAN_IFACE="eth0";
WAN_IP="88.191.xxx.xxx";

# Flushing tables
$IPTABLES -F
$IPTABLES -X
$IPTABLES -t nat -F

# Define default policy
$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT ACCEPT
$IPTABLES -P FORWARD ACCEPT

$IPTABLES -A INPUT -j ACCEPT -d $LAN;
$IPTABLES -A INPUT -j ACCEPT -m state --state ESTABLISHED,RELATED
$IPTABLES -A INPUT -j ACCEPT -p tcp --dport 22
$IPTABLES -A INPUT -j ACCEPT -p tcp --dport 80
$IPTABLES -A INPUT -j ACCEPT -p tcp --dport 9102
$IPTABLES -A INPUT -j ACCEPT -p icmp


# SSH in VZ access
$IPTABLES -t nat -A PREROUTING -p tcp --dport 22101 -d $WAN_IP -j DNAT --to-destination $V
Z101_WEB:22
$IPTABLES -t nat -A PREROUTING -p tcp --dport 22102 -d $WAN_IP -j DNAT --to-destination $V
Z102_RAILS3:22

Answer 3

I have had similar problems: I could not ssh into the template, and had no network connectivity inside the template. Nmap told me all ports were closed on the template.

I used a Ubuntu 10.04 lamp amd64 package, mentioned as a 'contributed' template on the OpenVZ wiki.

I suspect /sbin/modprobe was giving me a hard time, because the fixes mentioned here in the 'configuration' section got networking and ssh to work.