It's on a laptop running Ubuntu 14.04, where the WiFi
wlan0 is used to connect to Internet.
eth0 (RJ45) is set statically in
auto eth0 iface eth0 inet static address 192.168.11.168 netmask 255.255.255.0 gateway 192.168.11.100
The problem is, there is usually no cable connected to
eth0, so at boot the IP address is not set. And when a cable is connected (on a LAN) for a short period of time, the address has to be set
ifdown eth0 ifup eth0
and since the device the laptop connects to does stop and restart, the IP is lost and has to be set again.
That kind of configuration does not seem to fit for a laptop connecting at times to devices, which may reboot etc...
Is there a way to tell the system to keep that IP assigned to
eth0, whatever happens, cable disconnections, boot, etc... ?
It seems wicd was the culprit. Once I removed eth0 from its config, the IP address behaved more consistently. It's always ON, on boot, unplugged... I knew the good old interfaces file could be trusted!