Hi,
it might be a faulty port as Martin suggests. If it still doesn't work in a different port or with a switch then I'd be looking at the network settings on the foxsat.
I'm assuming it's set for automatic dhcp, i.e. the foxsat gets its network settings from the router.
Take a note of the current settings when it's working (system,network,configure-ethernet), the ip address will be something like 192.168.1.5 depending upon what's on your network.
Change the settings to manual and add something like 20 to the last digit of the ip address, i.e. make 192.168.1.5 to 192.168.1.25 or something you know to be a free address (192.168.0.3 to 192.168.0.23 etc. etc.) and keep all the other entries the same, i.e. subnet,router,dns as they were with dhcp. Apply the changes and test.
I'm guessing there's some power saving and wake-up on lan going on with your router and the foxsat is getting stuck on obtaining its network address via dhcp.
You say "since connecting with network cable", I take it you weren't previously connecting via a wifi dongle and if so you've removed the dongle.
There are pros and cons with both dhcp and manual, the main thing at the moment is to get your box working without having to play around with cables and rebooting
