 <p>Permanent network settings are stored in various files in <code>/etc/networking</code> and <code>/etc/network-scripts</code>. You could use <code>diff</code> to compare what's in those files between the system. However, that's just the network stuff (static v.s. dynamic, routes, gateways, iptables firewalls, blah blah blah). If there's no differences there, you'll have to start expanding the scope of your search.</p>