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I've just installed a XenServer 6.1. It came with a standard configuration, network 0 connected to NIC 0.

I created a VM but I can't reach any network beyond the host.

From the VM (, I try to ping

Trying to make it work, I brought the following changes to the host base configuration:

  • xe-switch-network-backend bridge
  • reboot
  • edit sysctl.conf:

    net.ipv4.ip_forward = 1
    net.ipv4.icmp_echo_ignore_broadcasts = 1
    net.ipv4.conf.all.arp_filter = 1
    net.ipv4.conf.default.proxy_arp = 1
  • run sysctl -p

  • stop iptables /etc/init.d/iptables stop
  • run iptables -A FORWARD -j ACCEPT

"Ifconfig -a" shows 4 interfaces: eth0, lo, vif12.0 (my VM) and xenbr0 (IP=, netmask=, gateway=

$ brctl show
bridge name   bridge id          STP enabled   interfaces
xenbr0        5000.042b21457249  no            eth0

After all that, my VM still can ping but not

The host can ping it.

Can someone tell me how to proceed and if bridging is the right thing to do?

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up vote 0 down vote accepted

I suceeded to make it work. The problem came probably from a conflict with the ILO adapter on the server.

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Hi Greg - thanks for following up with your answer. Could you elaborate on what the issue was and what you had to do to fix it? – Dan Apr 11 '13 at 12:06
I learned that ILO was working on the first onboard network adapter. But the first time I installed Xen Server, I was trying to set the management network on eth0. To solve this, I plugged the 3 adapters: now I use eth0 only for ILO, eth1 for the Xen management network and eth2 for the guests. It worked directly. Next, I encountered a problem with "mac address limitation" on the switch where the server was connected. The port of the switch was blocking the traffic for different mac addresses. – Icu Apr 15 '13 at 8:01
I think you mis-understand how the iLO works. The iLO port is dedicated and isn't directly visible to the operating system. – Dan Apr 15 '13 at 8:08

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