I have an 'interesting' network set-up question.
I have just acquired a TP-Link TL-WA5210G outdoor WiFi access point and range extender to use on our boat to improve connections to BT WiFi (e.g. FON and Openzone hotspots). It's working well (I'm using it now). Direct WiFi from my laptop was very marginal here, like it occasionally worked but not often, now I have a perfectly satisfactory, solid, WiFi connection.
However, configuring the WiFi extender is quite awkward. It defaults to IP 192.168.1.254 and you configure it on the web at that address (can be changed of course, but factory reset will go back to 192.168.1.254). When working as a WiFi relay though its DHCP server has to be turned off and you have to use WiFi to access the internet.
Currently I have the hardwired ethernet connection on this laptop disabled so that everything goes through the 'amplified by the TP-Link' which appears as 'BT WiFi with FON' in Network Manager.
It would be nice if I could enable the hardwired ethernet at the same time as the WiFi so that I can talk to the TP-Link router while the WiFi to the outside world is connected as well. So I guess I need:-
A static address for the laptop in the 192.168.1.xx range on its eth0 interface. This will work at home as well as long as I make sure it doesn't clash with anything else - that's easy enough. Will just the Network Manager 'manual' configuration do all that's needed?
Some sort of routing configuration that says:-
If there's only a WiFi connection use it for everything.
If there's only a hardwired connection us it for everything.
If there's both hardwired and WiFi then use hardwired for 192.168.1.xx addresses and WiFi for everything else.
Where/how do I set this up? I'm quite happy to edit configuration files (in fact I almost prefer it to a GUI). If it can be automated easily then good but if it requires a manual 'switch' from one to the other I won't be too fussed.