I'm not sure if this is the right place to post this but it is network related so here goes.

I've been asked to look at a system which is running slowly. It's running hardy on an intel Q9400 quad core CPU system which should be a pretty fast machine.

The most obvious symptom of this problem is that the terminal takes about 10 seconds to open instead of the usual fraction of a second.

What I've discovered so far is that the system has 2 network ports one configured to access the LAN and the other to connect directly to another piece of hardware using a different subnet. If the LAN is not connected the system runs slowly and if it is connected it runs at normal speed. It also makes no difference whether or not the second network port is connected.

I've looked at the system monitor and can see no abnormal network traffic or processes using a lot of CPU resources.

Does anyone have any ideas how to resolve this?