PfSense 2.1.2 on XEN 4 wont pass any traffic on virtual NICs
We are trying to run several pfSense 2.1.2 VMs on XEN4 Hypervisors running CentOS 6 but so far have been unsucesful.
We can build and boot the pfSense VMs no problem but when we try to access the Web GUI it fails and we then realised that any attempts to ping the pfSense LAN or WAN ips in or out from the pfSense shell fails.
It seems that the VMs are not passing any network traffic whatsoever. The NIC drivers in the pfSense VMs are re0 and re1 so standard Realtek 8139 drivers as far as I can see.
Has anyone else seen this or have you any ideas where to start troubleshooting?