[Aragorn]

It 'should' be a case of setting the XBox to Automatic wired connection -

Originally Posted by http://www.home-network-help.com/xbox-network.html

1) Go to Settings of Xbox Dashboard, select Network Settings.
2) You will find IP Settings, DNS Settings and other options.
3) Click IP Settings, you can select Automatic to obtain the IP and other network information from DHCP server or router automatically. If not, select Manual to set IP address, subnet mask and gateway manually.
4) After that, back to previous menu and select DNS Settings. Select Automatic to obtain DNS server information from DHCP server or router automatically, else select Manual to set it manually.