Instances launched on openstack cannot connect to anything on the lan, yet they happily reach the internet (google, yahoo, etc.)

Openstack setup:

  • Ubuntu 12.04 running Openstack Essex
  • Multi-node
  • 1 Controller
  • 1 Compute running nova-network

Dual ethernet cards on the servers. eth0 is on the office lan, eth1 is on the private lan.

  • Internal office lan: ( -
  • Openstack private lan:

Instances get floating ip in the following range:

An instance with a floating ip can be reached from the office lan. An instance is unable to reach the office lan directly (ping fails)

I assume it's a missing forwarding rule on the compute host.

compute routing table:

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
default         firewall001.hq.         UG        0 0          0 eth0        *          U         0 0          0 eth0        *      U         0 0          0 br100   *        U         0 0          0 virbr0

Instance routing table:

Routing tables
Destination        Gateway            Flags    Refs      Use  Netif Expire
default             UGS         2      184 vtnet0        link#1             U           3      162 vtnet0
plum.novalocal     link#1             UHS         0        0    lo0
localhost          link#2             UH          0        0    lo0

1 Answer 1


Turned out to be a routing issue.

The actual fix is unknown, but moving all the vm to a got me going.

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