I'm in the process of setting up 3-node stacked DRBD, and i'm experiencing a rather bizarre issue. Two nodes are located at the data center, and the 3rd node is located locally. The Primary and Secondary nodes are working as expected, however the 3rd node won't connect to the primary. If I ping the IP provided by heartbeat on the 3rd node it will return 100% packet loss, if I reset networking interfaces, ping will then return a few successful packets, but then stop returning any packets. I can't work out any reason why this would be behaving like this. All nodes are running Debian Squeeze, and the latest version of DRBD.