I've been trying to find the native IP/interface used when generating own router traffic, such as package upgrades, but I have been unable to find it. I am sure it must be a trivial setting, that I've must have come across multiple times without noticing, but I can't find it.
The scenario, is as follows:
One wireless IP address, ie 10.20.30.2, internal, not routable to the outside (at some point that network is not backwards routable, by design), one internal IP address in the ethernet port, ie 192.168.10.2, that routes traffic correctly (actually local clients work great).
As the router attempts to do a PING to anywhere, it will get no response, if you don't select manually the originating ip as the local ethernet one. When trying to update the packages, it will not resolve the DNS host, neither find the update server (obviously, as it is generating traffic from the 10.20.30.2).
The only way I've found to reliable solve this issue, is by reinstalling the configuration, and setting the ethernet address first.
Thanks in advance!