We have a brand new Dell PowerEdge C6220 fitted with 4 server modules. Everything appears to be in working order and Ubuntu Server 12.04 has been installed on one server module from a USB DVD drive. However, the network connection is behaving very strangely - it is very intermittent. In about 1 in 20 boots, the server gets a DHCP lease and a working network connection but anything from 10 seconds to 2 minutes later, the link drops. Unplugging the network cable and re-connecting usually restores the connection for about 10 seconds after reconnection but it fails again 10 secs - 2 mins later.
This is not an O/S problem as all 4 server modules fail to connect and get an IP address via DHCP even when using PXE, although about 1 in 20 attempts succeed for a short while before losing the connection again. The network the server is attached to is 100 Mbit/s fed from 3Com switches. No other system connected to this network is exhibiting any problems of this kind so I can only assume it is something to do with the Intel i350 on-board NIC.
Has anyone else experienced this problem? The server is currently unusable because of this and I thought I would ask here before contacting Dell support.